Thio-bis(alkyl lactone acid esters) and thio-bis-(hydrocarbyl diacid esters) are useful additives for lubricating compositions

ABSTRACT

Thio-bis-(hydrocarbyl substituted diacid materials), such as thio-bis-(polyalkyl lactone acid) and/or their precursors the adducts of sulfur chloride and unsaturated diacid materials, e.g., 4,8-bis-polyalkyl-4,8-dichloro-5-thiaundecane-1,2,10,11-tetracarboxylic acid bis-anhydride and their dehydrochlorinated analogs, when esterified with an alcohol, preferably a polyol, such as pentaerythritol, polypentaerythritol or a polyalkylene glycol with or without acid catalysts and/or metal template reagents yield thio-bis-(alkyl lactone acid esters) and thio-bis-(hydrocarbyl diacid esters) which can be characterized in part, as macrocyclic and/or macrocyclic-like structures, are useful as stable additives in lubricating compositions, e.g. as varnish inhibiting dispersants for lubricating oils and fuels.

This is a continuation of application Ser. No. 804,306 filed 12/3/85,which is Rule 60 Divisional of U.S. Ser. No. 528,213, filed 8/31/83,(now U.S. Pat. No. 4,568,756) which is a Rule 60 Divisional of U.S. Ser.No. 173,299, filed 7/24/80 (now U.S. Pat. No. 4,417,062), which is aDivisional of U.S. Ser. No. 954,051, filed 10/23/78 (now U.S. Pat. No.4,239,636), which is a continuation in part of U.S. Ser. No. 768,265,filed 2/14/77 (now U.S. Pat. No. 4,123,373) and U.S. Ser. No. 806,326,filed 6/13/77 (now U.S. Pat. No. 4,167,514) which is a Rule 60Divisional of U.S. Ser. No. 726,206 filed 9/24/76, (now U.S. Pat. No.4,062,786).

BACKGROUND OF THE INVENTION AND PRIOR ART

The present invention concerns hydrocarbon soluble thio-bis-(alkyllactone acid esters) and thio-bis-(hydrocarbyl diacid esters), theirmethod of preparation and their utility, preferably, in hydrocarbon fueland lubricating systems, as stable sludge dispersants, varnishinhibitors, antioxidants, antiwear agents and lubricity additives.

During the past decade, ashless sludge dispersants have becomeincreasingly important, primarily in improving the performance oflubricants and gasoline, in keeping the engine clean of deposits, andpermitting extended crankcase oil drain periods. One category of ashlessdispersants involves esters of alkenyl substituted acids, e.g.polyisobutenyl succinic acids, with polyols e.g., pentaerythritol, astaught in U.S. Pat. No. 3,381,022; however, such dispersants oftentimescontain olefinic unsaturation making them susceptible to oxidativedegradation especially under high severity conditions such as elevatedoil temperatures and extended drain intervals.

A second category involves chloro lactone ester dispersants prepared viathe esterification of alkenyl chloro lactone acids with pentaerythritolas taught in U.S. Pat. No. 3,755,173; however, the inherent propensityof such dispersants, or antirust compounds as taught in U.S. Pat. No.2,279,688 towards elimination of corrosive HC1 to give unsaturatedproducts, can promote decomposition of the hydrocarbon lubricant,corrode metal engine parts, and promote varnish deposition on theinternal surfaces of the engine. Thus, the effectiveness of dispersantsof either category, particularly at higher temperatures, can be markedlyimpaired by oxidative degradation. Besides, not only do such systemssuffer from instability problems, but the potency of such dispersantsoftentimes, owing to inherent limitations in their sludge bindingcapacity, diminishes with increasing severity of operating conditions.The present invention overcomes the shortcomings of the prior art bydesigning novel thio-bis-(polyalkyl lactone acid esters) andthio-bis-(hydrocarbyl diacid esters) with enhanced stability andpotency. The stabilization of these novel dispersant systems may beascribable to the lack of unsaturation and/or the presence of sulfidefunctionality which endow these systems with enhanced stability andantioxidant properties. The enhanced potency may be related, in part, tothe macrocyclic and/or macrocyclic-like configuration assumed by thepolar sulfur and oxygen (heteroatom) functionality in some of thedispersant molecules. Such circular-like arrangements of ligands endowthese novel systems with remarkable binding and/or chelation propertiesand in some instances, inclusion properties, making these dispersantsystems uniquely effective even under high severity conditions.

We propose herein, novel and improved dispersant systems based onhost-guest chemistry wherein the polar head of the host molecule(dispersant) assumes or is capable of assuming a macrocyclic-likeconfiguration so that the resulting circular-like array of heteroatoms(e.g. sulfur, oxygen and nitrogen), on the polar head effectively bindsguest ions and molecules, including metals and sludge components, withinthe cyclic-like structure, or between host molecules to form asandwich-like structure with guest molecules in the middle.

SUMMARY OF THE INVENTION

It has now been discovered that hydrocarbon-substituted thioethers,which feature, in part, vicinal lactone and ester functions, can bearranged in a macrocyclic-like configuration using novel syntheticmethods whereby a highly stable additive of enhanced dispersancy,enhanced viscosity properties, and antioxidant properties can berealized. This novel class of macrocyclic-like additive can berepresented, in part, as an ester of6,6'-thio-bis-(4,5,6-trisubstituted-3,5-carbolactone-1-hexanoic acid) asfeatured by the formula: ##STR1## wherein R is selected from the groupconsisting of hydrogen, hydrocarbyl and substituted hydrocarbylcontaining from 1 to 10,000, preferably 12 to 200, carbons with therestriction that at least one R has at least about 4 carbons; thebridging or coupling element, Y, is selected from the group consistingof S (thio), S--S (dithio), S═O (sulfinyl), SO₂ (sulfonyl), Se (seleno),S--(CH₂)_(z) S-- where z is a number of from 2 to 10, X, X₁ and X₂ areselected from the group consisting of hydrogen, alkyl, hydroxyl,acyloxy, hydroxyalkyl, CH₂ OCH₂ C(CH₂ OH)₃, and --O(CH₂ --CH₂ O)_(n) Hwhere n is l to 50 and preferably at least one X group contains ahydroxy moiety, and that typically X₁ and X₂ are hydrogen bonded so asto form a macrocyclic-like configuration. In some cases, depending onstoichiometry, the nature of the reactants, and the mode of synthesis,X₁ and X₂ together can represent a linking group such as O, S, S--S,N--alkyl, --CH₂ OCH₂, --CH₂ OCH₂ --C(CH₂ OH)₂ --CH₂ OCH₂ --, --O(CH₂ CH₂O)_(n) --, wherein n is 1-50; such linking groups create equimolar [(i.e., one mole of thio bis-(acylating agent) to one mole of polyol(1:1)] macrocyclic ring structures of varying sizes and compositiondepending upon the nature of the thio-bis-(acylating reagent) and thepolyhydric alcohol. Sometimes, X₁ and X₂ may bond to another molecule ofthio-bis(acylating agent) e.g. thio-bis-(lactone acid) in whichinstance, two acylating reactants essentially combine with two polyols(2:2) to yield structurally larger macrocyclic esters of doubledmolecular weight. Furthermore, equimolar ester products ofthio-bis-(acylating agent) and polyol are capable of forming, undersuitable reaction conditions, ever larger macrocyclic structures, e.g.(3:3), (4:4), etc. Usually, mixtures of linear and cyclic esteroligomers are formed, and the ratio of cyclic to linear oligomers is asensitive function of reaction conditions, and the nature of thereactants; however, with a judicious choice of experimental conditions,one can achieve a suitable mix of cyclic and linear esters for specificend users.

It is noteworthy that the presence of a metal ion such as lithium,sodium, potassium, copper, zinc, nickel and cobalt, or alcoholate ofsuch metals as titanium, tin and silicon, in catalytic or stoichiometricamounts during esterification or bridging, tends to increase the yieldof macrocycles over the products of competing linear polymerizations, aphenomenon known as the template effect. In such cases, the formation ofmacrocycles are presumably mediated via the template action of thesemetals. Obviously, such metal ion assisted cyclizations provide avariety of useful cyclic ligands and their complexes for additiveapplications. In such cases, the metal ion or alkoxide species,depending upon its effective size, forms a template about which thepolyol and thio-bis-(acylating agent) can react to form 1:1, 2:2, and3:3 and larger macrocycles in substantial yields. The ability to controlthe mode of esterification with certain ions and acidic solid phasesystems provides a convenient and novel approach to tailoring thecomposition of an ester product to meet specific viscosity andperformance requirements.

Preferred herein are mono- and dithio-bis-(alkyl lactone polyol estersand simple esters) of number average molecular weight (Mn) ranging fromabout 400 to about 140,000 prepared by the reaction of a thio-bis-(alkyllactone carboxylic acid) or its precursor, a S_(x) C1₂ --olefin diacidadduct wherein x is 1 or 2, with a simple alcohol such as methanol or apolyol such as pentaerythritol, polypentaerythritol, or polyethyleneglycol at about 20-240° C. or preferably 50-200° C. until theesterification and lactonization (where operative) events are completeby IR analysis. To achieve substantial lactone formation in theesterification of S_(x) C1₂ --olefin diacid adducts with polyols, theuse of soluble acids, or resin acids, or acidic solid phases such assilica gel, is essential.

These novel compounds described above are effective as dispersants,inhibitors, antiwear and/or lubricity additives which are particularlyuseful in lubricating oil compositions and are also useful as additivesin distillate fuel compositions and gasoline as well as syntheticlubricating oils and automatic transmission fluids. Thus, it is withinthe scope of this invention to dissolve a small but at least aneffective amount of said compounds of the invention in a majorproportion of a hydrocarbon material to provide useful hydrocarboncompositions.

These preferred hydrocarbon soluble compounds have at least 4 carbons inthe substantially saturated aliphatic hydrocarbyl groups with preferablyone carboxylic acid group of each terminal dicarboxylic acid functionconverted into a lactone ring and the other carboxylic acid groupconverted into a polyol ester as a result of the reaction of at least anequivalent amount of said thio-bis-(hydrocarbyl substituted diacidmaterial), including both the diacid and anhydride, and a molar amountof a polyol or polyalkylene glycol, having about 2 to 20 hydroxyl groupsand containing a total of 2 to 100 carbons.

The novel thio-bis-(alkyl lactone acid esters) of the present inventioncan be prepared by heating together thio-bis-(alkyl lactone acids oresters), or YC1₂ --polyalkene diacid or anhydride adducts (Y having themeaning previously given) with 1-2 moles of polyol via the conventionalmethod or by a template procedure. The latter option involvesesterification in the presence of a metal ion or alcoholate whichpresumably induces the reaction of condensing functional groups withinits coordination sphere (template effect) so as to generate macrocyclicesters in the equimolar reaction of thio-bis-(acylating agents) andpolyols.

The conventional method involves the esterification of thio-bis-(alkyllactone acid) and/or its precursor, the S_(x) C1₂ --olefin diacid adductwith 1-2 moles of polyol, preferably in the presence of an acidcatalyst, and is featured in the equation: ##STR2## wherein: R, Y, X₁and X₂ are as earlier defined in the formula representing, in part, thenovel class of macrocyclic-like additive; R₁ is hydrogen or an alkylgroup containing from 1 to 5 carbons; H+ represents an acid catalyst;and, i refers to a polyol reactant which can be represented by theformula ##STR3## wherein W can be X, X₁ or X₂.

The adduct depicted in the above equation is readily converted to theacid or simple ester by hydrolysis with water or esterification with aC₁ to C₅ monohydric alcohol.

It has been further discovered that other useful thio-bis-(acylatingagents) comprising (i) thio-bis-(alkenyl diacid/anhydride/ester)prepared via chlorosulfenylation of olefin diacids with sulfur halides,at higher reaction temperatures, and (ii) dithio-bis-(alkyldiacid/anhydride/ester) prepared by means of sulfur bridging with thiolsunder oxidative conditions, when subsequently esterified with a polyolafford novel additives possessing lubricating oil dispersancy, lubricitymodification and/or friction modification properties.

DETAILED DESCRIPTION OF THE INVENTION

In the following description of this invention, the reactants, i.e.,thio-bis-acylating agents, their formation via the bridging (orcoupling) of alkene diacid materials with a sulfur halide or a sulfurhalide equivalent such as a sulfenate ester-HC1 combination reagent or athiol-halogen combination reagent; the esterification reactions of thebridged acylating agents with polyols in the presence of acids and metaltemplating reagents, and utilization of the novel ester products are setforth below in detail.

THIO-BIS-(ACYLATING REAGENTS)

The preparation of the mono-or dithio-bis-(lactone alkanoic acid orester), mono-or dithio-bis-(alkene dioic acid or anhydride or ester) ordithio-bis-(alkane dioic acid or anhydride or ester) acylating agentsinvolve the sulfur halide coupling or bis-sulfenyl halide-inducedcoupling or the oxidative coupling of H₂ S or thioacid adducts of anolefin diacid. The olefin diacid is readily obtained via the reaction ofan olefin or a chlorinated olefin with an unsaturated C₄ to C₁₀dicarboxylic acid, anhydride or ester thereof, such as fumaric acid,itaconic acid, maleic acid, maleic anhydride, dimethyl fumarate, etc.The dicarboxylic acid material formed via the Ene reaction of an olefinwith maleic anhydride can be illustrated as an alkenyl-substitutedanhydride which may contain a single alkenyl radical or a mixture ofalkenyl radicals variously bonded to the cyclic succinic anhydridegroup, and is understood to comprise such structures as: ##STR4## withthe γ,δ-unsaturated isomers predominating and wherein R may be hydrogenor hydrocarbyl or substituted hydrocarbyl containing from 1 to about10,000 and more carbons with the restriction that at least one R has atleast 1 carbon, preferably from about 16 to about 400 carbons andoptimally from about 60 to about 100 carbons. The anhydrides can beobtained by well-known methods, such as the reaction between an olefinand maleic anhydride or halosuccinic anhydride or succinic ester (U.S.Pat. No. 2,568,876). In branched olefins, particularly branchedpolyolefins, R may be hydrogen, methyl or a long chain hydrocarbylgroup. However, the exact structure may not always be ascertained andthe various R groups cannot always be precisely defined in the Eneproducts from polyolefins and maleic anhydride.

Suitable olefins include butene, isobutene, pentene, decene, dodecene,tetradecene, hexadecene, octadecene, eicosene, and polymers ofpropylene, butene, isobutene, pentene, decene and the like, andhalogen-containing olefins. The olefins may also contain cycloalkyl andaromatic groups. The most preferred alkenyl succinic anhydrides used inthis invention are those in which the alkenyl group contains a total offrom 4 to 400 carbon atoms; and, at least 16 to 400 and more preferably60 to 100 for mineral oil systems.

Many of these hydrocarbyl substituted dicarboxylic acid materials andtheir preparation are well known in the art as well as beingcommercially available, e.g. 2-octadecenyl succinic anhydride andpolyisobutenyl succinic anhydride.

With 2-chloromaleic anhydride and related acylating agents,alkenylmaleic anhydride reactants are formed. Bridging of these productswith YC1₂ also afford useful precursors to thio-bis-(lactone ester)products. Preferred olefin polymers for reaction with the unsaturateddicarboxylic acids are polymers comprising a major molar amount of C₂ toC₅ monoolefin, e.g., ethylene, propylene, butylene, isobutylene andpentene. The polymers can be homopolymers such as polyisobutylene, aswell as copolymers of two or more of such olefins such as copolymers of:ethylene and propylene; butylene and isobutylene; propylene andisobutylene; etc. Other copolymers include those in which a minor molaramount of the copolymer monomers, e.g., 1 to 20 mole % is a C₄ to C₁₈non-conjugated diolefin, e.g., a copolymer of isobutylene and butadiene;or a copolymer of ethylene, propylene and 1,4-hexadiene; etc.

The olefin polymers will usually have number average molecular weights(M_(n)) within the range of 500 and about 140,000; more usually betweenabout 700 and about 10,000. Particularly useful olefin polymers have(M_(n)) within the range of about 700 and about 5,000 with approximatelyone terminal double bond per polymer chain. An especially valuablestarting material for a highly potent dispersant additive arepolyalkenes e.g. polypropylene and polyisobutylene, having about 90carbons.

The dicarboxylic acid materials (Diels-Alder adducts) formed via thereaction of a chlorinated olefin with maleic anhydride also useful inthe present invention, can be illustrated in part, by the followingstructures: ##STR5## where R is as previously defined. Usefulchlorinated olefins include chlorinated di-isobutylene, tri-isobutylene,polyisobutylene, tetrapropylene, polyisopropylene, and alkenes whichupon halogenation characteristically afford allylic halide structures.

Hemi-ester or diacid reactants can be constructed readily from theanhydride products obtained via the Ene process by the scission of theanhydride ring with a mole of alcohol or water. Normally, the ringopening process is effected by interacting equimolar amounts ofanhydride and alcohol or water at temperatures of 25° C. to about 120°C. without diluent or with a suitable solvent such as tetrahydrofuran,p-dioxane, 1,2-dimethoxy-ethane, etc. In conversions to the diacid,excess water may be added to accelerate the ring scission process. Withalcohols, excess alcohol may lead to some di-ester formation, andaccordingly equimolar reaction stoichiometry, is preferable. In theabsence of strong acid catalysts, however, excess alcohol can be used toeffect hemi-ester formation. Suitable alcohol reactants includemethanol, ethanol, isopropanol, butanol or other simple monohydricalcohols which can be removed readily by evaporation or distillation.

BRIDGING REACTIONS

The bridging or coupling of the precursor acylating agents can beachieved via a choice of synthetic options including (i) addition ofsulfur halides or bis-sulfenyl halides or alkyl sulfenate/HC1 reagent tounsaturated diacids, hemi-esters, diesters or anhydrides, (ii) theoxidative coupling of unsaturated acids previously thiylated with H₂ Sor R₁ C(═O)SH, where R₁ represents a C₁ -C₅ alkyl group, or (iii)reaction of α,ω-alkanedithiols, H₂ S, or a suitable thiylating agent,with epoxidized or halogenated alkene dioic acid or anhydride materials.Synthetic approaches (i) and (ii) are described in detail herein.

In contrast to the facile and effective modes of sulfur bridgingoutlined above, other possible synthetic options including thesulfurization of olefin diacid materials with elemental sulfur, and theEne reaction of alkenyl sulfides do not provide discernable amounts ofstable, sulfur-bridged olefin diacid materials.

The prior art clearly teaches that the sulfurization of alkenes withelemental sulfur gives complex mixtures of unsaturated, unstablepolysulfides and polymeric sulfides up to about 140° C., and at highertemperatures, ca. 170° C., the polysulfidic products owing to limitedthermal stability, undergo extensive decomposition to yield hydrogensulfide, thiols, 1,2-dithiole- 3-thiones and/or thiophenes as the majorproducts. These results are in complete harmony with published reportswhich elaborate upon the chemistry of sulfurized olefins: (See L.Bateman and C. G. Moore, "Organic Sulfur Compounds", edited by N.Karasch, Pergamon Press, New York, 1961, Vol. I., pages 210-228).Moreover, sulfurization of alkenylsuccinic anhydrides with elementalsulfur also generates thioanhydride products which tend to eliminatehydrogen sulfide when treated with protic reagents such as polyols.

Finally, the Ene reaction of disulfides with maleic anhydride does notengender the desired Ene product, but affords only low yields of2-alkylthiasuccinic acid derivatives in a neither clean norsynthetically attractive reaction. This observation is totallyconsistent with the prior art (See L. Field, "Journal of OrganicChemistry", Vol. 39, No. 14, p. 2110-2112 (1974)).

BRIDGING WITH SULFUR HALIDES

The preferred pathway to bridged acylating agents involves the reactionof sulfur halides, bis-sulfenyl halides or a sulfenate ester-HC1 reagentwith unsaturated diacids, hemi-esters, di-esters or anhydrides in thetemperature range of -60° C. to about 100° C., optimally from about 10°C. to 50° C. If desired, solvents comprising hydrocarbons such aspentane, hexane, heptane, cyclohexane, mineral oil; halocarbons such asmethylene chloride, chloroform, carbon tetrachloride, aromatics such astoluene, chlorobenzenes, xylene; ethers, such as diethyl ether andtetrahydrofuran (THF); and, acids such as acetic, propionic andtrifluoroacetic acid, can be used in favorably controlling viscosity andreaction temperature. The mode of addition of reagents is dictated byconvenience. Usually, the sulfur halide is added dropwise to anunsaturated diacid, ester, or acid anhydride, preferably diluted in aninert diluent. With reactive diluents, namely those containingunsaturates including aromatics, and olefins such as polyisobutylene,sufficient sulfur halide must be added to effect complete bridging ofthe olefin diacid reactants.

When the addition of one mole of sulfenyl halide to 2 moles of alkenedioic acid anhydride is conducted at low temperatures, e.g. -60° C. toabout 20° C., a discrete YC1₂ -anhydride adduct forms via theintermediacy of the 1:1 addition product as depicted in the equation:##STR6## with R and Y being the same as previously defined. Theanhydride reactants can be the same or different so that mixtures ofsymmetrical and unsymmetrical bridged anhydride products can beconstructed at will. Higher conversions to unsymmetrical adducts can beachieved by the interaction of equimolar amounts of YC1₂ and one type ofalkene dioic acid or anhydride at low temperatures to generate a 1:1adduct. Subsequent addition of a second type of unsaturated anhydrideaffords the unsymmetrical bridged acylating agent predominantly.

In some cases, it may be convenient to carry out bridging using an alkylsulfenate ester since such esters are readily converted to sulfurhalides upon treatment with a hydrohalide acid under mild conditions,e.g. 0-20° C. in the presence of alkene diacid. Alkyl sulfenate esters,such as di-isopropoxy sulfide and/or disulfide are highly versatile,stable precursors to sulfur halides and accordingly, can be combinedwith an olefin diacid reactant in the proper molar ratio (1:2) andeffectively bridge the diacid reagent via the in situ conversion of thesulfenate ester into sulfur halide by the gradual addition of gaseousHC1. Substantial yields of sulfur-bridged acylating agents can berealized via this novel route.

Increasing bridging temperature above about 50° C., and branching in thehydrocarbyl portion of the alkene dioic anhydride tend to accelerate theelimination of HC1 from the YC1₂ -alkene dioic anhydride adduct. Sinceunsaturated bridged products can be further sulfenylated with YC1₂reagent (re-addition), it becomes necessary in some cases, to modify thetheoretical 2:1 stoichiometry to effect complete bridging. Accordingly,at higher temperatures, i.e. from 50°-100° C., ratios in the range of1.5:1 to 1:1 may be required to realize higher conversions to bridgedstructures due to re-addition reactions, and the partial thermaldecomposition of the sulfur halide reactant at elevated temperatures.While more sulfur halide reagent becomes necessary to achieve coupling,the additional sulfur incorporated into the dispersant precursor (andoccasionally the diluent) tends to endow the resulting thio-etherproducts with enhanced oxidative stability.

When bridging in accord with the theoretical stoichiometry becomesdesirable, high purity chlorosulfenylating reagent (distilled SC1₂),lower sulfenylating temperatures, and select thio-(bis-acylatingreagents) comprising hemi-ester, and/or diacid reactants, dissolved in aminimal amount of olefinic diluent, provide useful synthetic options inrealizing more efficient coupling processes. The concept of bridginghemiester and/or diacid reactants which tend to be more amenable tolactonization is depicted in the equation: ##STR7## wherein R and R₁ arethe same as earlier defined. The YC1₂ addition to the alkenylhemi-ester, diester of diacid previously freed of olefinic diluents bysilica gel extraction, affords discrete adducts which can be lactonizedvia a temperature-sensitive, internal displacement of chloride by avicinal carboxylic acid or ester group. Chloride displacement withresultant lactonization circumvents the elimination of HC1 which wouldotherwise lead to thio-bis-(alkene dioic acid or esters) products.

It should be noted, however, that treatment of the latter sulfur-bridgedunsaturated acylating agent with polyol to effect its esterificationusually generates mixtures of thio-bis (lactone acid ester) and thio-bis(alkene diacid ester); however, selective conversions to thio-bis(lactone acid ester) can be achieved prior to or during esterification,by using acid catalysts comprising soluble acids such as sulfuric acid,alkyl sulfonic acids (where alkyl corresponds to a C₁ to C₆₀ aliphaticradical selected from the group consisting of open chain alkyl,isoalkyl, and cycloalkyl); alkyl aromatic sulfonic acids (where alkyl isdefined as above and the aromatic groups can be derived from benzene,toluene, xylene, mesitylene and naphthalene); suitable alkyl aromaticsulfonic acids include i-dodecyl benzene sulfonic acid (Petrostep A-60,Stephan Chemical Co.), i-dodecyl benzene sulfonic acid (Vltrawet 99LSfrom Arco Chemical CO.) and i-tetracosyl benzene sulfonic acid (SA 119,Esso Chimie, France); Lewis acids such as BF₃, BF₃ etherate, A1C1₃ ; andresin acids including resin sulfonic acids such as Amberlyst 15 (Rohmand Hass Company, Philadelphia, Pa.) and perfluorinated resin sulfonicacids such as NAFION-H (E.I. DuPont de Nemours and Co., Inc. Wilmington,DE are suppliers of NAFION perfluorosulfonic acid products); andfinally, acidic solid phase catalysts, including silica gel (activated,Grade H, mesh size 100-200 from Davison Chemical, Baltimore, MD),alumina (acid A1₂ O₃) silica alumina, zeolite, and certain clays. Silicagel-induced lactonizations are highly useful, since it is believed thatthe silica gel plays a dual role as a lactonization catalyst and as atemplate for generating in part, macrocyclic-like products.

As indicated above, sulfur halides including SC1₂, S₂ C1₂ and alkylsulfenate ester/HC1 reagent are suitable bridging agents. Bis-sulfenylhalides derived from alkane, heteroalkane, aromatic, heteroaromatic, andheterocyclic radicals such as ##STR8## are also useful coupling agents.

Oxidation of the mono-thio ether products (both intermediates and polyolesters) provides access to useful sulfoxide and sulfone derivatives. Avariety of inorganic and organic oxidizing agents can be used to effectthese conversions including hydrogen peroxide, peracids, hydroperoxides,e.g. t-butyl hydroperoxide, chlorine, positive halogen reagents, nitricacid, oxides of nitrogen, oxygen, ozone and metal oxides. The preferredoxidant is hydrogen peroxide usually in acetic acid and as necessary inan aromatic solvent, e.g. toluene. Oxidation with equimolar quantitiesof reactants at about 0° to 60° C. provides the sulfoxide in excellentyield. A 2:1 molar ratio of peroxide to said thio ether product producesthe sulfone derivative. The peroxide oxidation of sulfides of sulfonesis preferably carried out in the presence of catalytic amounts ofconventional oxidation catalysts such as tungsten, molybdenum, e.g.molybdenyl acetylacetonate, or vanadium salts.

MECHANISM OF BRIDGING WITH SULFUR HALIDES

The key feature of the addition reactions of sulfur halides, preferablysulfur chlorides or bis-sulfenyl chlorides is their intrinsic ability tocouple or bridge a wide variety of unsaturated acid materials in awell-defined manner; this key feature clearly distinguishes the behaviorof sulfur halides from other sulfur donors such as elemental sulfurwhich produces only complex, unstable and ill-defined mixtures ofsulfurized products. As indicated above, the sulfur halides addselectively to the point of unsaturation, with a 1:1 sulfenyl chlorideadduct being formed initially, followed by the addition of the latter toanother unsaturated acid to form a dichloro sulfide adduct as shown inthe above equation. The composition of the adduct hinges on (a) theposition of the double bond in said olefin diacid material, and (b) themode of sulfur halide addition, i.e. an electrophilic addition, asdetermined by steric and electronic factors. In such electrophilicadditions, it is assumed that an episulfonium ion intermediate isformed, although contributions from open ions have not been discounted.Scission of the intermediary episulfonium ion by halide ion from thesulfur halide yields mainly the dihalosulfide isomer depicted in theabove equations. The presence of other isomers, however, cannot beprecluded. Of greater significance in the assignment of structure to theproducts of the present invention is the nature of the lactones formedupon hydrolysis or alcoholysis of the adduct. The lactonization processseems to involve a carboxyl function either by displacing chlorine fromthe dichlorosulfide, ring-opening of an intermediary episulfonium ion oradding (via acid catalysis) the carboxy function to an unsaturated siteof the adduct.

Judging from the structure of the unsaturated acid reactants fromspectral evidence, it is believed that the thio-bis-(lactone acid orester) products are best illustrated by the structures featuring5-membered lactone rings as proposed in the above equations. Theformation of some six-membered lactones (and even larger ring lactones),however, has been observed by IR spectral analysis, particularly duringthe polyol or water-induced lactonization of S_(x) C1₂ -olefin diacidadducts. Accordingly, 6-ring (or larger ring) lactones and otherpositional isomers based on the position of sulfur in the bridgedstructures can also be present in the products of this invention.

BRIDGING WITH THIOLS

In another embodiment of the present invention, thio-bis-(acylatingagents) can be constructed via the (i) peroxide or (ii) acid-inducedaddition of H₂ S and/or thioacids to olefin diacid materials to givethiolactone acids and/or thiol-substituted diacids which are thenamenable to bridging via (a) oxidative coupling with C1₂, SO₂ C1₂, H₂O₂, or peracids or (b) displacement reactions with α,ω-alkylenedihalides, e.g. ethylene dichloride.

Alkene dioic acid materials (diacid anhydride or ester) can be readilyreacted with H₂ S and thioacids under both heterolytic (acid-induced)and homolytic (radical-induced) conditions. Typically, the acidcatalyzed reaction affords a product wherein sulfur becomes bonded tothe most substituted carbon atom, as shown by the equation: ##STR9##wherein R is as previously defined.

Hydrogen sulfide (usually added in about a two to ten fold excess)reacts with olefin diacid materials (here the anhydride) according tothe above equation at comparatively low temperatures, e.g. from about-70° C. to about 25° C. in the presence of ca. 0.1 to about 10 wt. % ofsuch acid catalysts as HC1, BF₃, or a chloride salt of A1, Zn, B, P, Sn,Ti, and Sn. The aforesaid hydrogen sulfide addition can also becatalyzed with etherates, alcoholates or hydrates of BF₃. The H₂ Saddition products can be isolated as the corresponding thiolactonederivatives owing to the facile lactonization of the mercapto derivativeas shown in the above equation. Both the mercapto and thiolactonederivatives can be readily bridged via oxidative coupling ordisplacement reactions in protic solvents such as water and alcohols.

A synthesis of isomeric thiol-substituted diacid material can also beeffected via the homolytic reaction of olefin diacid material withthiols and thioacids. Reactive thiols such as thioacetic acid addreadily to the least substituted olefinic carbon atom in alkene dioicacid reagents in the presence of small amounts, e.g. about 0.05 to 1 wt.% of peroxides such as benzoyl peroxide, di-tert-butyl peroxide, to givea thioacyl substituted alkane dioic acid material, which is thereafteroxidized with sulfuryl chloride in methanol to the correspondingsymmetrical disulfide product as shown in the equation: ##STR10##wherein T is a C₁ to C₅ acyl group, e.g. acetyl; κ refers to suchoxidants as C1₂, SO₂ C1₂, and H₂ O₂ ; and R and R₁ are the same aspreviously described.

As seen above, thiolactones and thiol-substituted diacid materials canbe easily bridged via oxidative solvolysis using a combination of anoxidant such as air, H₂ O₂, peroxide, chlorine or SO₂ C1₂, and a proticsolvent such as water, or alcohol. An alternate preparative option tobridging involves a nucleophlic displacement of the thiol-substituteddiacid reagent with α,ω-alkane dihalides including C1(CH₂)_(n) C1,C1(CH₂ CH₂ S)_(n) CH₂ CH₂ CH1 and C1(CH₂ CH₂ O)_(n) CH₂ CH₂ CH1, whereinn is a number from 1 to 10, and bis-chloromethylated aromatics,heteroaromatics and heterocycles.

ALCOHOL REACTANTS

1. Monohydric alcohols

Useful monohydric alcohols can be characterized by the formula R'OHwherein R' is an alkyl or heteroalkyl group containing from 1 to 24,preferably 1 to 12, carbons such as methyl, ethyl, propyl, butyl, hexyl,octyl, decyl, lauryl, stearyl and mixtures thereof; andheteroatomcontaining aliphatic radicals such as CH₃ O(CH₂ CH₂ O(_(n) CH₂CH₂ --, CH₃ S(CH₂ CH₂ S)_(n) CH₂ CH₂ --, (CH₃)₂ N(CH₂ CH₂ NCH₃)_(n) CH₂CH₂ --; etc., where n = 1-10, and1-aza-3,7-dioxabicyclo(3.3.0)oct-5-methanol. The resulting esters whenused as additive components for mineral lubricating oils and fuelsprovide improved properties of antiwear, anticorrosion, frictionmodification or lubricity modification.

2. Polyhydric alcohols

The polyhydric alcohols used in esterifying the thio-bis-(acylatingreagents) can have a total of 2 to about 100 carbon atoms and can berepresented by the formula: ##STR11## wherein: X₃ is hydrogen, C₁ to C₅alkyl, hydroxyl, hydroxyalkyl HO(CH₂)_(n) wherein n is 1-10,hydroxyalkoxy HO(CH₂ CH₂ O)_(n) --, wherein n is 1-40, hydroxyalkylthioHOCH₂ CH₂ S(CH₂ CH₂ S)_(n) --, wherein n is 1 to 10; andhydroxyalkylamino HO(CH₂ CH₂ NCH₃)_(n) --, wherein n is 1 to 10; and X₄and X₅ may be the same or different and represent hydrogen, C₁ to C₅alkyl and C₁ to C₅ hydroxyalkyl groups and their ester, ether, acetal orketal derivatives. Examples of useful acetals and ketals include monoand bis-formals of pentaerythritol; mono and bis-acetal and benzalanalogs of pentaerythritol; and the cyclic formal and acetal of HO(CH₂CH₂ O)_(n) H wherein n is 4-8.

With glycol and polyethylene glycol reactants, esterification ofsulfur-bridged acylating reagents preferably in the presence of templatereagents, affords in part, simple macrocycles and macrocyclic-likestructures (depending on reactant ratios), while reaction of polyolswherein X₄ and/or X₅ represent hydroxyalkyl substitutents, affords inpart, macrocycles and macrocyclic-like species with cage-likeconfigurations capable of entrapping ionic or charged species andthereby providing unique dispersant activity.

An especially preferred class of polyhydric alcohols for designingnovel, cage macrocyclic and macrocyclic-like ester products are typifiedby pentaerythritol, dipentaerythritol, tripentaerythritol,polypentaerythritols, sorbitol, mannitol, cyclohexaamylose,cycloheptaamylose and related polyhydric alcohols such as these preparedvia the aldol condensation of formaldehyde with ketones such as acetone,and cyclohexanone, e.g. 2,2,6,6-tetramethylol-1-cyclohexanol. In someinstances, enhancement of the above-described caging effect may becarried out by partially esterifying one or both the geminalhydroxyalkyl groups represented by X₄ and X₅ of the polyol with acarboxylic acid having from about 2 to 18 carbon chain which containssuch heteroatoms as nitrogen, sulfur and oxygen.

ESTERIFICATION PROCESS

The thio-bis-(lactone acid esters) and thio-bis-(hydrocarbyl diacidesters) of the present invention can be prepared via (a) a conventionalester synthesis or (b) a template procedure involving ester formation inthe presence of a metal salt, or alcoholate.

Using the conventional approach, we contemplate within the scope of thepresent invention the formation of esters from (i) the S_(x) C1₂ -olefindiacid anhydride adduct and its HC1-free analogs via scission of theanhydride ring with polyol in the presence of an acid catalyst, or (ii)the esterification of the thio-bis-(alkyl lactone acid) materials withpolyol alone or in the presence of an acid catalyst. The scission of theanhydride ring in option (i) affords a transient hemi-ester species viaattack of the polyol at the least congested carbonyl site in the adduct.The incipient carboxyl group of certain hemi-ester intermediates mayrapidly displace chloride ion in an intramolecular process to afford a5-, 6- or larger membered lactone ring. The size of such lactone ringswill depend on the position of the chlorine in the adduct, and thespecific carboxy group involved in the intramolecular displacement. Whenelimination of chloride in the S_(x) C1₂ -olefin diacid anhydridereactant occurs prior to hemiester formation, which is an event favoredat temperatures above about 50° C. especially in S_(x) C1₂ -branchedolefin diacid adducts, the free carboxy group is either furtheresterified to provide a thio-bis-(alkene dioate ester) product or addsto the point of unsaturation within the adduct to form 5-, 6- and/orlarger membered lactone rings, depending on the position of the doublebond. The preferred lactonization process is aided by the presence ofthe acid catalysts described previously.

Typically, the esterification method is carried out by adding about onemole of alcohol, preferably polyol, per 0.5 to 1 mole ofthio-bis-(lactone acid or ester) or S_(x) C1₂ -alkene diacid adduct orit HC1-free analog, with or without an inert diluent, in the presence ofan esterification catalyst, and heating the mixture at 20-240° C.,preferably 50-220° C. until reaction is complete by infrared analysis ofthe product as indicated by maximal absorptions for ester and lactonefunctionality.

Variations, however, in the molecular weight and composition of thesulfur-bridged acylating agent, as well as the molecular weight andpolyhydric character of the polyol may be necessary, depending uponutility, since these factors sensitively affect thehydrophilic-lipophilic balance, solubility and the viscosity of theadditive.

For example, it has been found that lactone esters obtained from thereaction of one mole of bis-thio-(alkyl lactone acid) or its S_(x) C1₂-olefin diacid adduct precursor (derived from polyisobutenyl succinicanhydride with M_(n) ≈1050 and a Saponification number of 78) with twomoles of pentaerythritol feature outstanding dispersant properties.Moreover, with higher polyhydric alcohols, for example, esters obtainedvia reaction of equimolar amounts of the above thio-bis-(acylating)agents and tripentaerythritol also featured outstanding dispersantactivity.

The superior stability and dispersant properties exhibited by thesulfur-bridged lactone esters and sulfur-bridged hydrocarbyl esters ofthe present invention over the prior art compositions, namely esters ofpolyisobutenyl succinic anhydride and polyols such as pentaerythritol,may be related in part, to the presence of sulfide functionality and inpart, to the macrocyclic and macrocyclic-like configurations assumed bythe polar heteroatoms in some of the dispersant molecules.

METAL ASSISTED CYCLIZATIONS

Although a wide spectrum of macrocyclic-like esters can be constructedvia the conventional approach, the template procedure offers a selectivesynthetic route to macrocycles and their complexes as well in theequimolar reaction of polyol and thio-bis-(acylating agent). In themetal ion assisted process, the cation presumably enhances yields ofmacrocycles by forming a template about which the sulfur-bridgedacylating agent and polyol molecules condense into a macrocyclicspecies. It is believed that complex formation in the hemiesterintermediate accelerates the intramolecular ester formation relative tothe intermolecular process which affords polymer product. Factors suchas metal ion size, and the length of the polyol reactant will dictatethe relative yields of 1:1, 2:2 and larger cyclic ligands formed in theequimolar reaction of the thio-bis-(acylating agent) and polyol. Ingeneral, the overall yields of cyclic products are enhanced at theexpense of linear oligomer as a consequence of the template effect.

Metal ions of such metals as lithium, sodium, potassium, calcium,copper, zinc, iron, and cobalt are useful template reagents; othereffective metal derivatives include the alcoholates of titanium,silicon, vanadium and zirconium.

The templating action of those metal species can be achieved by (1)adding the metal salt directly to the reaction mixture or (2)prereacting the metal ion with one of the reactants to form (i) themetal carboxylate of the thio-bis-acylating agent, (ii) the polyhydricalcoholate salt, or (iii) the metal carboxylate of a polyol hemi-esterwhich is subsequently bridged with a sulfur halide.

Thus, in accord with synthetic option (1), metal assisted cyclizationscan be achieved by simply adding a molar amount of a metal salt, e.g.cupric acetate, to an equimolar mixture of a thio-bis-(acylatingreagent), e.g. an SC1₂ -alkenyl succinic anhydride adduct and a polyol,e.g. tetraethylene glycol, and heating the mixture in a suitable diluentsuch as tetrahydrofuran or xylene at about 50-150° C. untilesterification (and lactonization) are complete by infrared analysis.Removal of by-product metal halide salt by filtration and solventremoval by rotoevaporation usually affords substantial amounts of thedesired ester product. Using similar preparative strategy, the additionof catalytic amounts of tetrabutyl titanate to a mixture of equimolaramounts of thio-bis-(lactone acid), e.g.,6,6'-bis-thio-(3,5-carbolactone-1-heneicosanoic acid) and polyol, e.g.,2,2,6,6-tetramethylol-1-cyclohexanol followed by refluxing the reactionmixture in xylene until ester formation was complete, affords uponwork-up, an ester product which is principally a mixture of macrocyclicesters. In the absence of tetrabutyl titanate, the same esterificationprocess affords increased amounts of polymeric ester product.

As indicated above, macrocyclic ester formation via option (2) can beaccomplished using several synthetic variations including (i) thereaction of a metal carboxylate salt of a thio-bis-(lactone acid) withan electrophilic glycol analog such as C1CH₂ CH₂ (OCH₂ CH₂)_(n) OCH₂ CH₂C1 wherein n is 0 to 20; (ii) the reaction of a sodium salt of a polyolsuch as tetraethylene glycol with a sulfur-bridged acylating agent suchas thio-bis-(lactone acid chloride) or a SC1₂ -alkenylsuccinic anhydrideadduct; or (iii) the process of forming a metal carboxylate of a glycolhemi-ester, prepared from 2 moles of an alkenylsuccinic anhydride and amolar amount of tetraethylene glycol, and subsequently bridging thehemi-ester with a sulfur halide.

Judging from gel permeation chromatography measurements on the esterproducts of these processes, it is evident that the presence of a metalion during esterification tends to increase the yield of macrocyclesover ester products from competing linear oligomeric processes. Theability to influence the mode of ester formation with metal salts andsolid phases such as silica gel provides a versatile approach to thedesign of ester products with superior viscosity and performancecharacteristics.

USE OF THIO-BIS-(ALKYL LACTONE ACID ESTERS) AND THIO-BIS-(HYDROCARBYLDIACID ESTERS) AS ADDITIVES IN OLEAGINOUS COMPOSITIONS

The oil-soluble sulfur-bridged lactone ester products of the inventioncan be incorporated in a wide variety of oleaginous compositions. Theycan be used in lubricating oil compositions, such as automotivecrankcase lubricating oils, automotive transmission fluids, etc.,generally within the range of about 0.01 to 20 wt. %, e.g. 0.1 to 10weight percent, preferably 0.3 to 3.0 weight percent, of the totalcomposition. The lubricants to which the bridged lactone polyol esterproducts can be added include not only hydrocarbon oils derived frompetroleum but also include synthetic lubricating oils such aspolyethylene oils; alkyl esters of dicarboxylic acid; complex esters ofdicarboxylic acid, polyglycol and alcohol; and alkyl esters of carbonicor phosphoric acids; polysilicones; fluorohydrocarbon oils, mixtures ofmineral lubricating oil and synthetic oils in any proportion, etc.

When the products of this invention are used as multifunctionaladditives having detergent and antirust properties in petroleum fuelssuch as gasoline, kerosene, diesel fuels, No. 2 fuel oil and othermiddle distillates, a concentration of the additive in the fuel in therange of 0.001 to 0.5 weight percent, based on the weight of the totalcomposition, will usually be employed.

When used as a friction modifier for automatic transmission fluids, theadditives of the invention preferably the thio-bis-(hydrocarbyl diacidmaterials) such as, for example, 6,6'-mono-ordi-thio-bis(3,5-carboloactone-1-heneicosanoic acid) are present inamounts ranging from about 0.05 to 2 weight percent based on the totalweight of the fluid.

When used as an antifoulant in oleaginous, e.g. mineral oil, streams inrefinery operations to prevent fouling of process equipment such as heatexchangers or in turbine ils, about 0.001 to 2 wt. % of the inventiveadditive, preferably a thio-bis-(alkene dioate pentaerythritol ester)will generally be used.

The additive may be conveniently dispensed as a concentrate comprising aminor proportion of the thio additive, e.g., 20 to 90 parts by weight,dissolved in a major proportion of a mineral lubricating oil, e.g., 10to 80 parts by weight, with or without other additives being present.

In the above compositions or concentrations, other conventionaladditives may also be present including dyes, pour point depressants,antiwear agents such as tricresyl phosphate or zinc dialkyldithiophosphates of 3 to 8 carbon atoms in each alkyl group, antioxidants,such as N-phenyl -naphthylamine, tert-octylaphenol sulfide,4,4'-methylene bis-(2,6-di-tert-butyl phenol), viscosity index improverssuch as ethylene-propylene copolymers, polymethacrylates,polyisobutylene, alkyl fumarate-vinyl acetate copolymers and the like,de-emulsifiers such as polysiloxanes, ethoxylated polymers and the like.

THIYLATED ADDUCTS OF S_(x) C1₂ AND OLEFIN DIACIDS

In another embodiment of the present invention, treatment of S_(x) C1₂-alkenyl succinic anhydride adducts and their dehydrohalogenatedproducts with thiylating agents affords thio- or sulfo-substitutedderivatives engendered by (a) the displacement of chloride from theadduct by thiol reagents such as H₂ S, thiol acids such as thioaceticacid, dialkyl dithiophosphoric acid; and alkane thiols, or (b) theaddition of one of the above thiol reagents or chloro sulfonic acid orits equivalent (SO₃) to a dehydrochlorinated adduct of S_(x) C1₂ andolefin diacid material using an acid-induced or free radical-includedaddition to the olefinic unsaturation in the thio-bis (alkene diacidanhydride). This invention will be further understood by reference tothe following examples, which include preferred embodiments of theinvention.

SYNTHESIS OF ALKENE DIACID REACTANTS

A wide spectrum of alkene diacid materials, amenable to sulfur bridgingreactions, can be designed via the reaction of maleic anhydride with anolefin or chlorinated olefin. Both routes to alkenylsuccinic anhydridesinvolve heating the olefin or chloro-olefin reactant and maleicanhydride together in the presence of catalytic amounts of inhibitor atabout 180-260° C. for 1-24 hours until sufficient adduct is formed.Depending on availability and cost of starting materials, a 1.1-2 foldexcess of either reactant can be employed to increase the rate ofadduction and yield of alkenyl succinic anhydride. When excess maleicanhydride is employed, varying amounts (10-40% yields) of alkenyl di-,tri-, and poly-succinic anhydrides accompany the mono-adduct togetherwith minor amounts (5-25% yields) of unreacted olefin. Since themono-adduct is the preferred species for the purpose of this invention,it is advantageous to employ excess olefin in adductions with maleicanhydride. High ratios (1.5-10) of olefin to maleic anhydride affordsubstantial yields (50-80%) of olefin diacid products comprising Enestructures as ##STR12## By way of contrast, the reaction ofchloroalkenes and maleic anhydride proceeds via an eliminationre-arrangement pathway to gave in part, Diels Alder products comprisingsuch structures as: ##STR13## the R group in the Ene or Diels-Alderadducts may be hydrogen, or hydrocarbyl each having from 1 to 400 andmore carbons. The most preferred alkenyl succinic anhydrides are thosederived from such olefins and chloroalkenes as isobutylene,diisobutylene, chloro diisobutylene, n-octene, tetrapropylene,n-octadecene, polypropylene, polyisobutylene (M_(n) ≈800 and 1050) andchloropolyisobutylene (M_(n) ≈800 and 1050). The monochloro olefins,judging from spectral and chemical behavior, are predominantly allylicin character.

The C₄ -C₁₈ olefins and chloro diisobutylene are reacted with maleicanhydride (excess alkene used), at atmospheric pressure or whenrequired, as with isobutylene, and diisobutylene, under pressure(120-260° C.) for 4-16 hours. The alkenyl succinic anhydride productsfrom C₄ -C₁₈ olefins and chloro diisobutylene were vacuum distilled andheart cuts were taken for sulfur bridging to give modelthio-bis-(acylating agents) essentially free of bridges alkenyl di-, andtri-succinic acid anhydrides.

The polyolefin diacid anhydrides were usually prepared by heating about1-2 moles of maleic anhydride with about 1 mole of polyolefin at about200-280° C. in the presence of an inhibitor (1-2 wt. % of PARABAR 441)at 1-200 psi for 8-16 hours. The degree of functionalization wasassessed by the (i) saponification number of the polyalkene diacidanhydride, and (ii) chromatographic analysis (on silica gel) ofpolyolefin diacid for active ingredient present in the reaction mixture.Judging from the saponification numbers and chromatographic analyses foractive ingredient, it appears that most polyalkenyl succinic anhydridescontained modest amounts (5-20 wt. %) of bis- and tri-succinicanhydrides and 10-30 wt. % of unreacted polyalkenes.

In the light of the compositional data for the polyalkenyl succinicanhydrides, the present invention also teaches the sulfur halide-inducedbridging of alkenyl bis- and tris-succinic anhydrides present in thevarious PIBSA and chloro-PIBSA reactants. Accordingly, when reference ismade to sulfur bridged PIBSA reactants and products, the presence ofbridged PIB(SA)_(y) (where y is 2, 3 or more) is implied in most cases.

The alkenyl succinic anhydride reactants used in designing the thio-bis(acylating) agents of the present invention are featured below:

    __________________________________________________________________________    ALKENYL SUCCINIC ANHYDRIDE (ASA)                                              PRECURSORS TO THIO-BIS-                                                       (ACYLATING AGENTS)                                                                                 Alkenyl  ASA                                                            Olefin                                                                              Succinic Sap.                                            Process                                                                            Olefin    Mol Wt (1)                                                                          Anhydride (ASA)                                                                        Number (2)                                                                          Mn (1)                                    __________________________________________________________________________    Ene  Isobutylene                                                                             57    Isobutenyl-SA                                                                          720   154                                                            (IBSA)                                                        Di-isobutylene                                                                          112   Di-isobutenyl-SA                                                                       553   210                                                            (DIBSA)                                                       n-octene  112   n-octenyl-SA                                                                           550   210                                                            (NOSA)                                                        tetrapropylene                                                                          168   tetrapropenyl-SA                                                                       410   228                                                            (TPSA)                                                        octadecene                                                                              252   octadecenyl-SA                                                                         310   375                                                            (OSA)                                                         polypropene     polypropenyl-SA                                                                        92    623                                                            (PPSA)                                                        polyisobutylene polyisobutenyl-SA                                                       758   (PIBSA)  84    776                                                      812   PIBSA    112   757                                                      1050  PIBSA    72    1080                                      Diels-                                                                             Cl--Diisobutylene                                                                       146   Cl--DIBSA(3)                                             Alder                                                                              Cl--polyiso-                                                                            800   Cl--PIBSA(4)                                                                           80    751                                            butylene                                                                      (4.1% Cl)       Cl--PIBSA                                                                              112   771                                            Cl--polyiso-                                                                            1010  Cl--PIBSA                                                                              103   1044                                           butylene                                                                      (4.0% Cl)                                                                __________________________________________________________________________     (1) Polyolefin and polyalkenylsuccinic anhydride molecular weights            determined by Gel Permeation Chromotography (GPC).                            (2) Saponification number according to AMS 500.23.                            (3) 3,3,4,5tetramethyl-1,2,3,6-tetra-hydrophthallic anhydride.                (4) For convenience, Ene and DielsAlder PIBSA will be identified as PIBSA     and Cl--PIBSA, respectively.                                             

A. SYNTHESIS OF MODEL THIO-BIS-(ACYLATING AGENTS)

In the following examples, synthetic procedures are described forbridging the Ene and Diels-Alder products depicted above and theirdiacid, hemi-ester and diester analogs. Various modes of bridging as afunction of bridging agent, bridging temperature, and reactant ratiowill be outlined in detail. Moreover, a number of examples will also beput forth to illustrate the conversion at the S_(x) C1₂ -olefin diacidadducts into other useful thio-bis-(acylating agents) including bridgedalkene diacid anhydrides, and alkyl lactone acids, and esters.

In the first seven examples, the coupling (or bridging) of a modelalkene diacid reactant, i.e., isobutenyl succinic anhydride (IBSA) withseveral bridging agents including SC1₂, S₂ C1₂, and SeC1₄ using varioussolvents and temperatures; and the conversion of S_(x) C1₂ -IBSA adductsinto lactones, sulfoxides and sulfones will be elaborated.

EXAMPLE A1 Adduct of SC1₂ and isobutenyl succinic anhydride (IBSA)

Two tenths mole (30.8 g) of isobutenylsuccinic anhydride (IBSA) weredissolved in 100 ml of methylene chloride and 0.1 mole (10.3 g) of SC1₂were added dropwise at 0° C. while under a nitrogen blanket. Thereaction was very exothermic, but no HC1 evolution was observed. Whenthe addition was completed, the reaction mixture was allowed to warm upto room temperature and stirred for a few hours. The methylene chloridewas removed by rotoevaporation at 50° C. for 2 hours. The concentratefeatured an infrared spectrum with an intense anhydride carbonylabsorption band at about 5.67 microns and a gel permeation chromogramwith a single peak corresponding to the bridged product.

EXAMPLE A2 Adduct of SC1₂ and IBSA at 100° C.

About 77 g (0.5 mole) of isobutenyl succinic were dissolved in a verysmall amount of THF (10 ml) and heated slowly to 100° C. Then, 0.35 mole(40 g) of SC1₂ were added dropwise for a period of one half hour. Whenthe addition was completed, the reaction mixture was kept at 100° C. forhalf an hour while stirring under a nitrogen blanket and then nitrogensparged at 100° C. for another half hour. The infrared spectrum of theproduct featured a strong anhydride carbonyl absorption band at 5.65microns; GPC analysis indicated that the product was completely bridged.

EXAMPLE A3 6,6'-Thio-bis-(5-methyl-3,5-carbolactone-1-hexanoic acid)

Two tenths mole (30.8 g) of isobutenyl succinic anhydride (IBSA) wasdissolved in 100 ml of THF and 0.1 mole (10.3 g) of SC1₂ were added at0° C. The reaction mixture was warmed up to room temperature and stirredfor four hours. Then, 0.2 mole (3.6 g) of water was added and thereaction mixture was refluxed for several hours to assure completelactonization. Infrared analysis of the reaction product revealedcomplete conversion to the desired thio-bis-(lactone acid).

In the same manner,6,6'-dithio-bis-(5-methyl-3,5-carbolactone-1-hexanoic acid) was preparedvia the reaction of IBSA and S₂ C1₂ according to the procedure describedabove.

EXAMPLE A4 6,6'-Thio-Bis-(5 Methyl-3,5--Carbolactone-Hexanoic Acid ViaIsobutenyl Succinic Acid

Two tenths mole (30.8 g) of IBSA were dissolved in 100 ml of THF andmixed with 0.2 mole (3.6 g) of water. The reaction mixture was refluxeduntil infrared analysis indicated complete conversion to the diacidproduct. Then, the solution was cooled to room temperature and 0.1 mole(ea. 10.3 g) of SCl₂ was added dropwise for a period of half an hour. Anexothermic reaction took place and gas evolution was observed. Themixture was refluxed in THF for 4 hours to assure complete conversion.The infrared analysis of the product confirmed the presence of thedesired thio-bis (lactone-acid).

EXAMPLE A5 Sulfoxide of the SCl₂ -ISBA Adduct

Two tenths mole (ca 30.8 g) of isobutenyl succinic anhydride weredissolved in 100 ml of methylene chloride. The resulting solution wasstirred at 0° C. and then bridged via the dropwise addition of 10.3 g(ca 0.1 mole) of SCl₂. After the addition was completed, the reactionmixture was allowed to stir at room temperature for a few hours.

To the above adduct, 20.2 g (0.1 mole) of 85% meta-chloroperbenzoic acidwas added spoonwise for a period of one hour. An external cooling bathwas provided to keep the reaction about room temperature. After theaddition was completed the clear solution was stirred at roomtemperature for several hours. During this period the chlorobenzoic acidwhich precipitated out of solution was filtered. The filtrate was cooledto 0° C. and more acid was filtered. This operation was repeated severaltimes until the infrared spectrum of the filtrate showed the absence ofmetachlorobenzoic acid.

The CH₂ Cl₂ solution was dripped into a large volume of ether and awhite solid formed. The mass spectrum of the product featured asubstantial peak at m/e 354 for the dehydrochlorinated bridged sulfoxideproduct.

EXAMPLE A6 Sulfone of the SCl₂ -IBSA Adduct

Oxidation of the SCl₂ -IBSA adduct described in Example A5 with 0.2 moleof m-chloroperbenzoic acid afforded the desired sulfone derivative.

EXAMPLE A7 Adduct of Selenium (IV) Chloride and IBSA

Three tenths (ca 46.2 g) of IBSA were dissolved in 100 ml of chloroformand 25 g (0.11 mole) of selenium (IV) chloride were added at roomtemperature while under a nitrogen blanket. The exothermic reaction wasmaintained about 20° C. via an external cooling bath. No HCl evolutionwas observed. When the addition was completed, the reaction mixture wasallowed to stir at room temperature for 12 hours--the chloroform wasrotoevaporated at 100° C. for an hour. The GPC analysis of the residueshowed substantial bridging.

The following examples illustrate the (1) sulfenylation of diisobutenylsuccinic acid, anhydride, DIBSA hemi-ester, and diester with SCl₂ and S₂Cl₂ at ambient and 100° C. temperature, with and without solvent usingreactant ratios of 1:1 and 2:1; and (2) conversions of the S_(x) Cl₂-olefin diacid adducts to thio-bis-(alkyl lactone acids and esters) andthio-bis-(alkene diacids and diesters).

EXAMPLE A8 Dehydrochlorinated Adduct of SCl₂ and DiisobutenylsuccinicAnhydride

Three-tenths mole (63 g) of diisobutenylsuccinic anhydride (DIBSA)dissolved in 100 ml of methylene chloride was bridged with 0.15 mole(15.5 g) of sulfur dichloride (SCl₂) by adding the SCl₂ dropwise to theanhydride at about room temperature. External cooling was needed tomaintain the exothermic bridging process at about 25° C. The reactionmixture was maintained over nitrogen for 2 days, and subsequentlyrotoevaporated at about 50° C. for 2 hours. The concentrate featured anIR spectrum with an intense carbonyl absorption band at about 5.67microns and analyzed for 58.92% carbon, 7.44% hydrogen, 7.84% sulfur and4.17% chlorine. Theory requires 55.07% C, 6.93% H, 6.12% S, and 13.56%Cl.

EXAMPLE A9 Dehydrochlorinated Adduct of S₂ Cl₂ and DiisobutenylsuccinicAnhydride

A tenth-mole (21.0 g) of diisobutenylsuccinic anhydride in 150 ml ofchloroform and 0.05 mole (6.8 g) of sulfur monochloride in 150 ml ofHCCl₃ were simultaneously added dropwise to 200 ml of chloroform atabout 25° C. After addition, the mixture was stirred at ca 25° C. for 2days and concentrated by rotoevaporation at ca 25° C.

The concentrate analyzed for 10.31% chlorine and featured a gelchromatogram dominated by a peak corresponding to the S₂ Cl₂-diisobutenylsuccinic anhydride adduct. Refluxing the adduct in dioxanefor 24 hours gave a concentrate consisting primarily of 5,5'dithio-bis-(4-neopentyl-3(4)-pentene-1,2-dicarboxylic acid anhydride)which analyzed for 2.12% chlorine. A plausible structure for thethio-bis-(alkene diacid anhydride) product in parts is shown below:##STR14##

In a similar manner, diisobutenylsuccinic anhydride (0.05 mole) wassulfenylated with an equimolar amount of sulfur monochloride (S₂ Cl₂).The gel chromatogram of the solvent-free product showed a dominant peakascribable to the sulfur-bridged anhydride product.

EXAMPLE A10 High Temperature Reaction of SCl₂ with DiisobutenylsuccinicAnhydride

Two-tenths mole (42 g) of diisobutenylsuccinic anhydride being stirredat ca 100° C. under a nitrogen atmosphere, was treated dropwise with 0.1mole (10.3 g) of sulfur dichloride. The reaction temperature (100° C.)was maintained by the controlled addition of SCl₂. Following thecompletion of SCl₂ addition, the stirred mixture was maintained at 100°C. using external heating. Gel chromatography of the product revealedthat a substantial portion (ca 66%) of the anhydride was bridged by theSCl₂. Complete bridging could be achieved by the further addition ofSCl₂ to the mixture.

EXAMPLE A11 Adduct of SCl₂ and Diisobutenylsuccinic Anhydride ViaEquimolar Reaction

Bridging of 0.05 mole (10.5 g) of diisobutenylsuccinic anhydride(dissolved in 50 ml of CH₂ Cl₂) was effected by the dropwise addition ofan equimolar amount (0.05 mole, 5.2 g) of SCl₂ to the anhydride at ca25° C. The concentrated product featured an IR spectrum with a stronganhydride carbonyl absorption band at 5.67 microns and a gelchromatogram with an intense band corresponding to the bridged anhydrideproduct.

EXAMPLE A12 6,6'-Thio-Bis-(5-Neopentyl-3,5-Carbolactone-1-Hexanoic Acid)

Two tenths mole (42.0 g) of diisobutylene succinic anhydride (DIBSA) wasdissolved in 100 ml of THF and 0.1 mole (10.3 g) of SCl₂ were added.During addition, the reaction temperature climbed to about 35° C. andHCl evolution occurred. The mixture was refluxed for four hours and thenheated to 100° (THF distilled off) for two more hours to effect completedehydrohalogenation.

The residue was cooled and dissolved in THF and 0.2 mole of water andtwo drops of concentrated sulfuric acid were added. The mixture wasrefluxed for several hours. Infrared analysis revealed completeconversion to the desired thio-bis-lactone acid pictured below.##STR15##

EXAMPLE A13 6,6'-Dithio-Bis-(5-Neo-Pentyl-3,5-Carbolactone-1-HexanoicAcid)

A tenth mole (21 g) of diisobutenylsuccinic acid was prepared viahydrolysis of the corresponding anhydride in refluxing tetrahydrofuran(THF). After IR analysis indicated complete conversion to said diacid,the reaction temperature was elevated to 95° C. by distilling off asufficient volume of THF solvent. While maintaining a temperature of ca.95°-100° C., 0.05 mole (6.9 g) of sulfur monochloride was added dropwiseto the stirred solution. HCl evolution was noted. Rotoevaporation of thereaction mixture gave a concentrate of the product which featured an IRspectrum dominated by an intense lactone carbonyl absorption band at5.68 microns. The gel chromatogram of the residue show a large bandascribable to the desired sulfur-bridged lactone acid.

EXAMPLE A14 6,6'-Thio-Bis-(5-Neo-Pentyl-3,5-Carbolactone-1-HexanoicAcid)

Two tenths mole (42.0 g) of DIBSA was dissolved in 100 ml of THF and 0.1mole (10.3 g) of SCl₂ were added. During addition the reactiontemperature climbed to about 35° C. and HCl evolution occurred. Themixture was refluxed for four hours and then heated to 100° (THFdistilled off) for two more hours to effect completedehydrohalogenation.

The residue was cooled and dissolved in THF and 0.2 mole of water andtwo drops of concentrated sulfuric acid were added. The mixture wasrefluxed for several hours. Infrared analysis revealed completeconversion to the title thio-bis-(lactone acid).

EXAMPLE A15 Sulfur Bridged Lactone Ester Reactants Dimethyl6,6'-Thio-Bis-(5-Neo-Pentyl-3,5-Carbolactone-1-Hexanoate)

A tenth mole of mono-methyl diisobutenylsuccinate was dissolved in 100ml of xylene and 0.05 mole of SCl₂ was added dropwise to the stirredxylene solution maintained at ca. 25° C. The mixture was refluxedovernight and rotoevaporated for three hours at 90° C. IR analysisrevealed that the hemi-ester/SCl₂ adduct was completely converted to thedesired thio-bis-lactone methyl ester. A plausible structure for thesulfur-bridged bis-lactone is shown below: ##STR16##

EXAMPLE A16 Tetramethyl5,5'-Dithio-Bis-(4-Neo-Pentyl-3(4)-Pentene-1,2-Dicarboxylate)

A tenth mole (25.6 g) of dimethyl diisobutenyl succinate in 100 ml CH₂Cl₂ was treated dropwise with 0.05 mole (6.8 g) of S₂ Cl₂ at roomtemperature. After addition, the reaction mixture was stirred at roomtemperature for several hours and rotoevaporated at 50° C. for 2 hours.The concentrate featured a gel chromatogram with a dominant peakconsistent with the sulfur-bridged ester product,dithio-bis-(alkenylsuccinic acid dimethyl ester), corresponding to aM_(n) of about 400. Heating the adduct at 225° C. for 2 hours afforded amaterial with a gel chromatogram similar to that prior to heating.Clearly, the thermolytic conditions imposed on the bridge structuresfailed to cleave the sulfur-linked acid esters, and demonstrates thestability of the S-bridged esters towards the thermal conditions imposedduring the esterification of the bridged structures.

The following examples illustrate the bridging of diisobutenyl succinicanhydride (DIBSA) via successive thiolation and oxidation reactions.

EXAMPLE A17 Tetramethyl5,5'-Dithio-Bis-(4-Neo-Pentyl-4-Methyl-1,2-Butanedioate)

Two tenths mole (42 g) of diisobutenylsuccinic anhydride was dissolvedin 200 ml of CH₂ Cl₂ and cooled to -70° C. Ten grams of gaseous hydrogensulfide were then condensed into the reactor at -70° C. The stirredreaction mixture was subsequently treated with gaseous BF₃ (1bubble/sec) for 3 hours at -70° C. The clear colorless solution turnedyellow after 1 hour, and upon warming to room temperature, assumed adark red color.

The solvent was removed and the reaction mixture heated to 120° C. for 1hour. IR analysis of the mixture showed the presence of thiolactoneacid. Further reaction with methanol at 80° C. for 1 hour gave thethiolactone ester shown which was dissolved in ether, washed severaltimes with aqueous NaHCO₃, and dried over MgSO₄.

Vacuum distillation of the residue afforded 29 g of a fraction, b.p.128°-130° C. (0.04 mm), which featured an IR spectrum with strongcarbonyl absorption bands at 5.73 and 5.86 microns and a proton spectrumconsistent with a 5-ring thiolactone ester. Elemental analyses showed60.59% carbon, 8.53% hydrogen and 12.00% sulfur. Theory requires 60.42%C, 8.58% H and 12.41% sulfur. The proposed structure for the thiolactoneester is featured below: ##STR17##

Oxidation of said thiolactone ester with a mole equivalent of t-butylhypochlorite in methanol afforded the desired dithio-bis-ester productin high yields.

EXAMPLE A18 Tetramethyl 5,5'-Dithio-Bis-(4-Neo-Pentyl-1,2-Pentanedioate)

A tenth mole (7.6 g) of thioacetic acid and 0.05 mole (10.5 g) ofdiisobutenylsuccinic anhydride were dissolved in 30 ml of ether andstirred at room temperature overnight. Distillation of the mixture freedof solvent gave a fraction (8.0 g) boiling at 180°-185° C. (0.1 mm). TheIR spectrum of the product recrystallized from ether/pentane (m.p.72°-73° C.) featured intense anhydride and thiol ester carbonylabsorption bands at 5.64 and 5.95 microns. The crystalline productanalyzed for 59.03% C, 7.57% H and 10.99% S. Theory requires 58.70% C,7.57% H and 11.20% S. The proton and carbon magnetic spectra wereconsistent with the structure of the thioacetyl anhydride intermediateas shown below: ##STR18## wherein R is neopentyl and T is CH₃ C═O.Oxidation of said thioacetyl anhydride was smoothly effected via thedropwise addition of 0.02 mole (2.7 g) of sulfuryl chloride to ca 50 mlof a methanol solution of 0.02 mole (5.72 g) of the thioacetylanhydride. The addition produced an exotherm and the reactiontemperature peaked at ca 50° C. The mixture was stirred at ambienttemperatures for about an hour. Gel permeation chromatography (GPC) ofthe reaction mixture indicated that oxidative coupling was ca 80%complete; accordingly, additional SO₂ Cl₂ (ca 0.5 g) was added until theGPC of the reaction mixture showed only a product peak. Upon standing,the reaction mixture crystallized. The solids recrystallized fromether/pentane melted at 82°-83° C. and, featured: an IR spectrum with adominant carbonyl band at 5.72 microns, a proton spectrum with a doublemethyl proton signal centered at 6.3 tau, and a mass spectrum with amolecular ion peak at 578. The data are completely consistent with thebridged structure shown below. The product analyzed for 58.24 % carbon,8.48% hydrogen, 10.99% sulfur, and 22.24% oxygen. Theory requires:58.09% C; 8.70% H; 11.08% S and 22.11% O. ##STR19## wherein R isneopentyl.

The following examples describe unsuccessful attempts to prepare stablebridged derivatives of Ene and Diels-Alder adducts (DIBSA and Cl-DIBSA)via sulfurization with elemental sulfur. Also illustrated is theattempted Ene reaction of alkenyl disulfide with maleic anhydride, whichafforded 2-alkylthiasuccinic acid anhydride rather than the desiredthio-bis-(acylating agent).

EXAMPLE A19 Sulfurized Diisobutenyl Succinic Anhydride

A mixture of 10.5 g and (0.05 mole) of diisobutenylsuccinic anhydride(DIBSA) and elemental sulfur (0.05 mole, 1.6 g) was heated to 205° C.and maintained at this temperature with magnetic stirring for 5 hours.IR analysis of the reaction mixture showed the appearance of a strongabsorption band at 5.9 microns (ascribable possibly to thioanhydride)and a shift in the C═C absorption band from 6.05 to 6.22 microns(attributable possibly to a sulfur-induced isomerization of the C═Cdouble bond). Gel permeation chromatography (GPC) featured an intensepeak maximum corresponding to that observed for diisobutenylsuccinicanhydride. A peak in the gel chromatogram corresponding tosulfur-bridged diisobutenylsuccinic anhydride products, i.e.,thio-bis-(diisobutyl succinic anhydride) was conspicously absent.

EXAMPLE A20 Sulfurization of Cl-DIBSA

A mixture of 3,3,4,5-tetramethyl-1,2,3,6-tetrahydrophthallic anhydride(3.6 g, 0.017 mole), 0.27 g (0.0085 mole) of sulfur and 20 ml ofdichlorobenzene was heated to reflux for about 72 hours. The product wasfreed of dichlorobenzene by rotoevaporation; the gel chromatography ofthe residue revealed a peak maximum which coincided with the startingmaterial.

EXAMPLE A21 Reaction Product of Diisobutenyl Sulfide and MaleicAnhydride

A half mole (144 g) of diisobutenyl disulfide (prepared via addition ofS₂ Cl₂ to 2,4,4-trimethyl-2-pentene) and a mole (98 g) of maleicanhydride were combined and heated gradually to about 170° C. andmaintained at this temperature (with stirring) for 3 hours. The clear,orange-colored reaction mixture turned pitch black during heating, andsolids began to deposit on the walls of the reactor. Only part (ca 115g) of the hot reaction mixture could be decanted. The black,resinous-like mass adhering to the reactor weighed ca 127 g. Vacuumdistillation of the decanted reaction mixture afforded about 14 g ofproduct, b.p. 115-120 (0.5 mm). The IR spectrum of the distillatefeatured characteristic carbonyl absorption bands for an anhydrideproduct and analyzed for 18.15% sulfur.

The following examples relate to the bridging of Diels-Alder adductswith SCl₂ and S₂ Cl₂ and the conversion of the S_(x) Cl₂ -olefin diacidanhydride to the corresponding thio-bis-(lactone acid).

EXAMPLE A22

Two tenths (30.4 g) mole of cis-1,2,3,6-tetrahydrophthalic anhydride(cis-4-cyclohexene-1,2-dicarboxylic anhydride) was dissolved inchloroform (200 ml) and 0.1 mole (10.3 g) of SCl₂ were added dropwise tothe well stirred solution at room temperature. The SCl₂ additionincreased the temperature to 53° C. and the addition was completed atabout 53° C. Midway during SCl₂ addition the solution turned hazy andsome solids separated from solution. After addition the mixture wasallowed to cool and the solids (20 g) were isolated by filtration. Thesolid product featured an IR spectrum with strong anhydride carbonylabsorption, melted at 177°-178° C., and analyzed for 46.88% C, 4.22% H,7.68% S, and 14.93% Cl. Theory for the adduct (C₁₆ H₁₆ Cl₂ O₆ S)requires 47.18% C, 3.96% H, 7.87% S, and 17.41% Cl.

About 10.2 g (0.025 mole) of the adduct of cis1-2,3,6-tetrahydrophthalic anhydride and SCl₂ were dissolved in 100 mlof THF and mixed with 1 g of water and two drops of concentratedsulfuric acid. The mixture was refluxed in THF for four hours, then theTHF was distilled off and replaced by p-dioxane. The dioxane solutionwas refluxed for about 24 hours. The dioxane was stripped and theresidue was dissolved in a mixture of methylene chloride and ether. Awhite solid separated. The solid featured an infrared spectrumconsistent with the desired lactone-acid product.

EXAMPLE A23

A mole (152 g) of cis-1,2,3,6-tetrahydrophthalic anhydride (cis-4cyclohexene-1,2-dicarboxylic anhydride) was dissolved in 400 ml ofchloroform and 0.50 mole (68 g) of sulfur monochloride were addeddropwise to the well stirred solution at room temperature. Initially theS₂ Cl₂ addition did not produce an exothermic reaction, but the reactiontemperature rose to about 33° C. by the end of the addition, thesolution was allowed to stir at room temperature for 8 hours, some solidseparated during this period. The solid was filtered and yielded 166 gof a white crystalline material which melted at 154°-156° C. andanalyzed for 44.03 wt. % C, 4.12 wt. % H, 14.75 wt. % S and 15.43% Cl.The solid product featured an IR with strong anhydride carbonylabsorption. The filtrate was evaporated obtaining an oily residue withan infrared analysis and GPC similar to the solid product.

EXAMPLE A24

About 11.0 g (0.025 mole) of the adduct of cis1-2,3,6-tetrahydrophthalic anhydride and S₂ Cl₂ were dissolved in 100 mlof THF and mixed with 1 g of water and two drops of concentratedsulfuric acid. The mixture was refluxed in THF for four hours, then theTHF was distilled off and replaced by p-dioxane. The dioxane solutionwas refluxed for about 24 hours. The dioxane was stripped and theresidue was dissolved in a mixture of methylene chloride and ether. Awhite solid separated. The solid featured an infrared spectrumconsistent with the desired lactone-acid product.

EXAMPLE A25 Sulfenylation of Cl-DIBSA with SCl₂

Approximately 2.08 g (ca 0.01 mole) of3,3,4,5-tetramethyl-1,2,3,6-tetrahydrophthallic anhydride were dissolvedin 50 ml of anhydrous ether and stirred at room temperature under anitrogen blanket. Then, 0.5 g (ca 0.005 mole) of SCl₂ were addeddropwise. No HCl evolution was observed. The reaction mixture wasstirred at room temperature overnight and then added dropwise into alarge volume of pentane. It yielded 1.2 g of a white solid which showedto be the sulfur-bridged product of the nitrogen, producing 1.4 g of anoily substance. The GPC of the oily material showed mainlysulfur-bridged anhydride product.

In the ensuing examples, the bridging of n-octenylsuccinic anhydride(NOSA), diacid, hemiester and silica gel-bound NOSA with suchsulfenylating agents as SCl₂, S₂ Cl₂, Se₂ Cl₂, 1,2-ethane-bis-sulfenylchloride, 1,3,4-thiadiazole-2,5-bis-sulfenyl chloride, and a novel alkylsulfenate ester-HCl combination reagent using various experimentalconditions are elaborated.

Methods for converting the S_(x) Cl₂ -NOSA adducts to thio-bis (lactoneacids and esters) are also described.

EXAMPLE A26 Adduct of SCl₂ and n-Octenylsuccinic Anhydride

Three moles (630 g) of n-octenylsuccinic anhydride (NOSA) were dilutedin a liter of CH₂ Cl₂ and stirred at room temperature. Then 1.5 moles(154 g) of SCl₂ in 500 ml of CH₂ Cl₂ were added dropwise. The exothermicreaction peaked to 50° C. initially and external cooling was applied tomaintain reaction temperature at about 25° C. No HCl evolution occurred.After stirring the reaction mixture for an hour after the SCl₂ addition,the solvent was removed by evaporation with a mild stream of nitrogen.The solid that separated from solution during solvent evaporation wasisolated (40 g) and after being recrystallized from CH₂ Cl₂, melted at149°-150° C. and analyzed for 55.45% C, 7.17% H, 5.73% S and 11.4 % Cl.The adduct, C₂₄ H₂₆ O₆ SCl₂ requires 55.06% C, 6.93% H, 6.13% S, and13.55% Cl. The infrared spectrum featured an intense anhydrideabsorption at 5.67 microns, and a proton spectrum consistent with thestructure shown below.

The concentrate obtained from the supernatant weighed 745 g and featuredan IR spectrum similar to that shown for the solid. The yield ofanhydride-SCl₂ adduct was virtually quantitative. A structure for one ofthe dominant bridged isomers formed in the SCl₂ -anhydride reaction isdepicted below: ##STR20##

EXAMPLE A27 S₂ Cl₂ -n-Octenylsuccinic Anhydride (NOSA) Adduct

A mole (210 g) of n-octenylsuccinic anhydride was dissolved in a literof ether and a half mole (67.5 g) of sulfur monochloride (S₂ Cl₂) wasadded dropwise to the stirred solution at room temperature. Anexothermic reaction occurred and the addition was completed underrefluxing conditions. The reaction mixture was stirred overnight andthen concentrated by rotoevaporation at 50° C. for 2 hours. The productfeatured an IR spectrum with a prominent anhydride carbonyl band at 5.65microns, and analyzed for 49.33% C, 6.04% H, 10.7% S and 12.6% Cl.Theory for the S₂ Cl₂ -n-octenylsuccinic anhydride adduct (C₂₄ --₃₆ Cl₂O₆ S₂) requires 51.88% C, 6.53% H, 11.54% S, and 12.76% Cl.

EXAMPLE A28 6,6'-Thio-Bis-(3,5-Carbolactone-1-Undecanoic Acid)

228 g (1.0 mole) of n-octenyl succinic acid, prepared via the hydrolysisof NOSA at 80° C., were dissolved in 200 ml of tetrahydrofuran (THF) andstirred at room temperature while 52 g (0.5 mole) of SCl₂ were addeddropwise. The reaction was exothermic and HCl evolution was observedduring and after the addition which took about one hour. When theaddition was completed, the reaction mixture was allowed to stir at roomtemperature overnight; a white solid formed upon standing. The solid wasfiltered, collected and dried (43 g). The infrared analysis of the whitepowder showed it to be the desired thio-bis-(lactone acid) whichanalyzed for 59.81% C, 7.68% 26.42% O, and 6.52% S (theory requires:59.23% C, 7.87%, 26.30% O and 6.59% S). The filtered reaction mixturewas then refluxed in THF for a few hours to effect complete reaction.Further work-up of the reaction mixture afforded more white solidsamounting to a quantitative yield of product. In accord withexpectations, GPC analysis featured a single band with a peak maximum ofM_(n) 480; and mass spectral analysis revealed a molecular ion at m/e486, in harmony with the proposed structure shown below: ##STR21##

EXAMPLE A29 Adduct of 1,2-Ethane-Bis-Sulfenyl Chloride andN-Octenylsuccinic Anhydride

A tenth mole (21.0 g) of n-octenylsuccinic anhydride dissolved in 100 mlof methylene chloride was bridged with 0.05 mole (8.2 g) of1,2-ethane-bis-sulfenyl chloride via the dropwise addition of the latterto the anhydride at 0° C. over a 15-minute period. The reaction mixturewas stirred overnight and rotoevaporated. The IR spectrum of theconcentrate featured a strong anhydride carbonyl absorption band at 5.65microns. The gel permeation chromatogram of the product featured asingle peak corresponding to the bridged adduct.

Treatment of the adduct product with a tenth mole of water at 70° C. foran hour afforded the corresponding lactone acid,6,11-dipentyl-3,5:14,12-bis-carbolactone-7,10-dithiahexadecane-1,16-dioicacid in quantitative yield. The IR spectrum of the lactone productfeatured strong lactone and carboxylic acid carbonyl absorption bands at5.68 and 5.88 microns.

EXAMPLE A30 Adduct of Selenium (I) Chloride and NOSA

Three tenths mole (63.0 g) of NOSA were dissolved in 100 ml of CHCl₃ and34.5 (0.15 mole) of selenium (I) chloride were added dropwise at roomtemperature. The reactor mixture was stirred at room temperature for 24hours. The CHCl₃ solution was rotoevaporated until constant weight andthe residue showed by GPC a maximum peak corresponding to the bridgedproduct.

EXAMPLE A31 Dimethyl 6,6'-Thio-Bis-(3,5-Carbolactone-1Undecanoate)

A half-mole of the adduct of SCl₂ and n-octenylsuccinic anhydride wasadded to 500 ml of xylene containing 32 g of methanol. The mixture wasallowed to stir overnight and heated to reflux for about four hours. Theproduct was then rotoevaporated for three hours at 70°-80° C. The finalproduct featured an IR spectrum with intense lactone and ester carbonylabsorption at 5.63 and 5.78 microns, and analyzed for 60.48% carbon,8.30% hydrogen, and 6.48% sulfur. The thio-bis-lactone ester (C₂₆ H₄₂ O₈S) requires 60.67% C, 8.23% H and 6.23% S.

The same ester lactone was easily prepared via the addition of SCl₂ tothe mono-methyl ester of n-octenyl succinic acid.

EXAMPLE A32 Dimethyl 6,6'-Dithio-Bis-(3,5-Carbolactone-1-Undecanoate)

Four-tenths mole of the adduct of S₂ Cl₂ and n-octenylsuccinic anhydrideand 0.8 mole (25.6 g) of methanol were dissolved in 200 ml of chloroformand stirred at room temperature for four days, refluxed in 16 hours, androtoevaporated at 80° C. for three hours. The product showed an IRspectrum with intense lactone and ester carbonyl bands and analyzed for57.19% carbon, 7.93% hydrogen, and 10.54% sulfur. Theory for the methylester product (C₂₆ H₄₂ O₈ S₂) requires 57.11% carbon, 7.74% hydrogen and11.73% sulfur.

The same lactone ester could be readily prepared via the addition of S₂Cl₂ to the monomethyl ester of n-octenylsuccinic acid.

EXAMPLE A33 6,6'-Dithio-Bis-(3,5-Carbolactone-1-Undecanoic Acid)

A half-mole (114 g) of n-octenylsuccinic acid (prepared via hydrolysisof n-octenylsuccinic anhydride at 80°) in 500 ml of chloroform wastreated dropwise with a quarter mole (37.8 g) of sulfur monochloride (S₂Cl₂ ) at room temperature. The mixture was then refluxed for severalhours (strong HCl evolution). Infrared analysis of the reaction mixtureshowed the presence of the desired lactone acid. The correspondingmonothio product can be prepared in the above-described manner withSCl₂.

EXAMPLE A34 Thio-Bis-(Lactone Acid) Via Addition of SCl₂ to SilicaGel-Bound N-Octenylsuccinic Anhydride

About 42 g (0.2 mole) of NOSA were dissolved in 200 ml of n-octaneadmixed with about 200 g of silica gel. An infrared spectrum of theoctane layer showed that all of the NOSA had been adsorbed to the silicagel. Then, 10.3 g (0.1 mole) of SCl₂ were added dropwise to the slurry,and an exothermic reaction took place. The mixture was stirred at roomtemperature for 2 hours and 3.6 g (0.2 mole) of water were added. Thewell-stirred mixture was refluxed in octane for about 8 hours. Then-octane was decanted and the silica gel was extracted three times with200 ml aliquots of THF (tetrahydrofuran). The THF was evaporated and asemisolid product was obtained. The infrared and MS spectral data fullyconfirmed that the product was the desired 6,6'-thio-bis-(3,5carbolactone-1-undecanoic acid).

EXAMPLE A35 Thio-Bis-(Lactone Ester) Via the HCl-Induced Reaction ofDiisopropoxy Disulfide with NOSA

About 42 g (0.2 mole) of NOSA were dissolved in 100 ml of THF andstirred at room temperature under a nitrogen blanket, while 18.2 g (ca0.1 mole) of diisopropoxy disulfide were added. Then, hydrogen chloridegas was slowly bubbled into the stirred solution at room temperature forabout 3 minutes. An exothermic reaction took place upon the addition ofgaseous HCl. The reaction mixture was stirred at room temperature for afew minutes and then refluxed in THF with one drop of concentratedsulfuric acid for about 8 hours. The THF was stripped and an oilyresidue was obtained. The residue featured an infrared spectrumcharacteristic of the sulfur bridge lactone ester. GPC analysisindicated complete bridging.

EXAMPLE A36 Bridging of NOSA Via Sulfenylation with1,34-Thiadiazole-2,5-Bis-Sulfenyl Chloride

Two-tenth mole (42 g) of n-octenyl succinic anhydride (NOSA) weredissolved in 100 ml of CHCl₃ and 0.1 mole (21.9 g) of 1,3,4-thiadiazole2,5-bis-sulfenyl chloride in 100 ml of chloroform were added dropwisefor a period of 15 minutes. An external cooling bath was provided tokeep the addition at room temperature. The reaction mixture was thenstirred at about 25° C. overnight. The solution was filtered and thefiltrate was concentrated with a stream of nitrogen. The oil residuefeatured an infrared spectrum with strong anhydride carbonyl absorptionband at 5.65 microns. GPC analysis revealed that complete bridging hadbeen achieved. Spectral analyses were in full accord with the desiredthio-bis-(acylating agent).

In the examples that follow, the sulfur bridging oftetrapropenylsuccinic anhydride (TPSA) and octadecenylsuccinic anhydride(OSA) and its diacid analog, with SCl₂ and S₂ Cl₂ using varioustemperatures and solvents, will be described.

EXAMPLE A37 Adduct of S₂ Cl₂ and Tetrapropenylsuccinic Anhydride

A mole (266.4 g) of tetrapropenylsuccinic anhydride dissolved in 300 mlof CH₂ Cl₂ and a half mole (68 g) of sulfur monochloride in 200 ml ofCH₂ Cl₂ were added dropwise and simultaneously into a reactor containing500 ml of CH₂ Cl at about 25° C. and then the reaction mixture wasstirred overnight. Removal of solvent by evaporation gave a concentratecontaining 4.73% chlorine and featuring an infrared spectrum with anintense anhydride carbonyl absorption band at 5.65 microns.Rotoevaporation of the concentrate at 100° C. for 4 hours gave an adductwhich analyzed for 3.19% chlorine and gave a gel permeation chromatogramcharacterized by a dominant band for the sulfur-bridged anhydrideproduct.

EXAMPLE A38 Dehydrochlorinated Adduct of SCl₂ and n-Octadecenyl SuccinicAnhydride (OSA)

Two hundred grams (0.57 mole) of n-octadecenyl-succinic anhydride weredissolved in 150 ml of chloroform. The resulting solution was stirred atroom temperature and then bridged via the dropwise addition of 29.4 g(0.286 mole) of sulfur dichloride. The bridging event was sufficientlyexothermic to reflux the chloroform diluent. Evolution of HCl gas wasnoted during the SCl₂ addition. Refluxing was continued for severalhours after addition by applying external heating to the reactant.Rotoevaporation of the mixture for 2 hours at 100° C. afforded theS-bridged anhydride adduct. Gel permeation chromatography revealed thatcoupling with SCl₂ was virtually complete. The S-coupled anhydrideadduct featured an intense carbonyl absorption band at 5.68 microns andanalyzed for 4.65% sulfur and 3.88% chlorine. The chlorine analysisindicates that the adduct had undergone extensive dehydrochlorination.

EXAMPLE A39 Adduct of S₂ Cl₂ and Octadecenylsuccinic Anhydride

Two hundred grams (0.57 mole) of n-octadecenyl succinic anhydridedissolved in 150 ml of chloroform was bridged via the dropwise additiveof 38.6 g (0.286 mole) of sulfur monochloride (S₂ Cl₂) at roomtemperature. The bridging reaction caused a gradual exotherm (solventbegan refluxing) accompanied by the evolution of HCl. Refluxing wascontinued after S₂ Cl₂ addition for about 24 hours. Rotoevaporation at100° C. for several hours gave a concentrate which featured a gelpermeation chromatogram consistent with the expected sulfur-bridgedanhydride adduct product. The adduct analyzed for 6.99% sulfur, and5.29% chlorine, and featured an IR spectrum dominated by an anhydridecarbonyl absorption band at 5.67 microns.

The chlorine analysis is consistent with a mixture comprising thedichlorosulfide, mono-chlorosulfide and unsaturated sulfide products.

EXAMPLE A40 6,6'-Thio-Bis-(3,5 Carbolactone-1-Heneicosanoic Acid)

Two-tenths mole (73.6 g) of octadecenylsuccinic acid was dissolved in500 ml ether and a tenth mole (10.3 g) of SCl₂ was added dropwise to thestirred ether solution at about 25° C. The addition was exothermic(ether refluxed) and HCl evolution occurred. The mixture was refluxedfor about 8 hours. Upon cooling solids separated from solution. Thesolid product featured an infrared spectrum with prominent lactone andcarboxylic acid carbonyl absorptions at 5.62 and 5.82 microns, melted at158°-163°, and analyzed for 69.01% C, 10.17% H, 4.37% S and 16.74% O.Gel permeation chromatography revealed that coupling of the diacid withSCl₂ was virtually complete to the lactone acid structure. Theory forthe thio-bridged lactone acid (C₄₄ H₇₈ O₈ S) requires 68.88% C, 10.25%H, 4.18% S and 16.69% O.

Further refluxing the supernatant gave four more crops of product with acombined weight of 50 g. The yields were quantitative. The proposedstructure for the title thio-bis-(lactone alkanoic acid) is illustratedbelow: ##STR22## wherein R is n-C₁₅ H₃₁.

EXAMPLE A41 6,6'-Dithio-Bis-(3,5-Carbolactone-1-Heneicosanoic Acid)

Two-hundred grams (0.54 mole) of n-octadecenyl succinic acid weredissolved in a liter of CHCl₃ and 36.7 g (0.272 mole) of sulfurmonochloride (S₂ Cl₂) were added dropwise to the stirred solution atroom temperature. The exothermic process was accompanied by vigorous HClevolution. After refluxing the mixture for about eight hours, thesolution was cooled and solids separated. Filtration gave 19 g of solid(m.p. 131°-136° C.) which featured an IR spectrum with intense carbonylbands at 5.62 and 5.72 microns, and analyzed for 66.42% C, 9.63% H, and8.22% S. Theory for the adduct (C₄₄ H₇₈ O₈ S₂) requires 66.12% C, 9.84%H, and 8.02% S. Rotoevaporation of the supernatant gave a solid productin high yield.

B. SYNTHESIS OF MACRO THIO-BIS-(ACYLATING AGENTS)

The following Examples describe the sulfenylation of polyisobutenylsuccinic acids, anhydrides and hemiesters with SCl₂ and S₂ Cl₂ to givethio-bis-(acylating agents).

Several examples also teach the use of solid phase synthesis whereinsilica gel-bound PIBSA is successively (a) bridged via sulfenylationwith sulfur halide and (b) lactonized directly on the solid phase toafford thio-bis-(lactone acids and esters).

EXAMPLE B1 Thio-Bis-(Polyisobutyl Lactone Acid)

Approximately 130 g of polyisobutenyl succinic acid M_(n) 776, preparedvia hydrolysis of PIBSA having a Sap. No. of ca 84 were dissolved in 400ml of chloroform and 0.05 mole (5.3 g) of SCl₂ was added dropwise to thestirred solution. After refluxing the mixture overnight, two drops ofsulfuric acid were added, the solvent was stripped off, and the mixtureheated at about 100° C. overnight. The product featured an infraredspectrum with strong carbonyl absorption bands in the 5.6-5.8 micronregion and analyzed for 1.69% sulfur and 0.09% chlorine. The IR spectrumof the diethylamine-treated product revealed a strong lactone carbonylband at 5.63 microns.

EXAMPLE B2 Thio-Bis-(Polyisobutyl Lactone Acid)

Ca. 0.1 mole (130 g) of PIBSA (M_(n)) of 776 having a Sap. No. of ca. 84was dissolved in 100 ml of dioxane and 0.05 mole (5.3 g) of SCl₂ wasadded dropwise to the well-stirred solution at ca. 25° C. The mixturewas then refluxed for four hours (HCl evolution noted). At this point, 4g of water acidified with three drops of concentrated sulfuric acid wereadded and the mixture was further refluxed for 24 hours. The mixture wasfiltered through basic Celite and rotoevaporated at 90° C. for severalhours. The concentrate featured an IR spectrum with strong absorptionbands in the 5.6-5.8 micron region, and analyzed for 1.55% sulfur and0.09% chlorine.

EXAMPLE B3 Dithio-Bis-(Polyisobutyl Lactone Acid)

Five hundred grams (0.385 moles) of PIBSA having an (M_(n)) of 776 and aSap. No. of 84 were dissolved in 60 ml of methylene chloride and cooledto 0° C. While stirring at 0° C. under a nitrogen blanket, 26 g (0.192moles) of sulfur monochloride were added dropwise over a period of halfhour. The reaction mixture was allowed to warm up to room temperatureand stirred for about ten hours.

One-half of this product was diluted in 100 ml of p-dioxane and 6.9 g ofwater (ca. 0.38 moles) were slowly added. The reaction mixture wasrefluxed for ten hours in the presence of a catalytic amount of sulfuricacid (HCl evolution occurred during reflux). Thereafter, the solvent wasremoved by rotoevaporation and the mixture further heated to 130°-140°C. for one hour. The product featured an infrared spectrum with strongabsorption bands in the 5.6-5.8 micron region (lactone acid) andanalyzed for 2.43 wt. % sulfur and 0.05 wt. % Cl. The IR spectrum of thediethylamine treated product revealed a strong lactone carbonyl band at5.63 microns.

EXAMPLE B4 Dithio-Bis-(Polyisobutyl Lactone Acid Methyl Ester)

A tenth mole (130 g) of polyisobutenylsuccinic anhydride (PIBSA) ofM_(n) 776 and having a Saponification Number of about 84 was dissolvedin 100 ml of THF and a tenth mole (3.24 g) of methyl alcohol was added.The well-stirred solution was heated to about 60° C. until its infraredspectrum showed complete conversion of the anhydride to the desiredPIBSA hemiester.

To one-half of the above reaction mixture, 4.5 g (0.039 mole) of S₂ Cl₂were added dropwise while stirring at room temperature, under a nitrogenblanket. The reaction mixture was stirred at 25° C. for ten hours andthen heated to 120° C. for another 10 hours with nitrogen sparging.

The concentrate featured an IR spectrum with strong absorption bands inthe 5.6-5.8 micron region, characteristic of lactone and ester carbonylabsorption bands.

EXAMPLE B5 Dithio-Bis-(Polyisobutenylsuccinic Anhydride)

About 200 g (ca 0.154 moles) of PIBSA having a M_(n) of 1080 and a Sap.No. of 72 were dissolved in 100 ml of methylene chloride. While stirringat room temperature under a nitrogen blanket, 10.4 g (0.077 moles) ofsulfur monochloride were added dropwise for a period of 15 minutes. Thereaction mixture was allowed to stir at room temperature overnight.

One-half of the above adduct was heated to 150° C. for approximately 4hours. Analytical data on the dehydrohalogenated residue showed 2.08 wt.% sulfur and 0.15 wt. % chlorine.

EXAMPLE B-6 Adduct of SCl₂ and Silica Gel Extracted PIBSA

About 200 g of diluted Ene PIBSA having a Saponification No. of 84 andM_(n) 776 were dissolved in one liter of heptane. The solution was mixedwith 600 g of silica gel and stirred at room temperature for abouttwelve hours. The heptane layer was decanted, and the silica gel waswashed twice with 500 ml aliquots of heptane.

The PIBSA bound silica gel was subsequently extracted with one liter ofboiling THF. Rotoevaporation at 80° C. for 2 hours afforded 101 g of apolyisobutylene and oil-free PIBSA residue which featured aSaponification Number of 118.8, a GPC maximum peak of M_(n) 1227, and avapor phase osmometry mol. wt. of 1090.

About 10 g of the neat PIBSA (ca. 0.01 mole) were dissolved in 50 ml ofTHF and stirred at room temperature while 0.8 g (ca 0.0075 mole) of SCl₂were added dropwise. The reaction mixture was stirred at roomtemperature for twelve hours. Rotoevaporation of the THF solvent gave aresidue which featured an IR spectrum with a strong anhydride carbonylabsorption band at 5.65 microns, a gel permeation chromatogram having amaximum peak at 1482 and featuring a molecular weight of 2177 accordingto vapor phase osmometry (VPO). The analytical data clearly show thatthe SCl₂ bridging of neat PIBSA was virtually quantitative.

The following examples illustrate a novel solid phase synthesis ofthio-bis-(acylating agents), wherein the PIBSA is purposely bound, oradsorbed, on a solid phase such as silica gel, and subsequently bridgedwith a sulfenylating agent such as SCl₂. Frequently, the adsorbed sulfurbridged PIBSA product lactonizes directly on the silica gel surface inthe presence of water or an alcohol.

EXAMPLE B7 Thio-Bis-(Polyisobutyl Lactone Acid) Via Sulfenylation ofSilica Gel-Bound PIBSA with SCl₂

Approximately 100 g of Ene PIBSA of M_(n) 776 and Sap. No. of 66 weredissolved in one liter of hexane and stirred at room temperature while400 g of silica gel were added. After stirring the slurry for severalhours, the hexane was decanted and silica gel was washed twice with 500ml of hexane. The hexane fraction was evaporated producing 60 g ofmaterial. The silica gel-bound PIBSA was stirred in heptane while 2.1 g(ca. 0.02 mole) of SCl₂ were added. The reaction mixture was stirred atroom temperature for a few hours and then refluxed in heptane containingsmall amounts of water for about 12 hours. At the end of the refluxingperiod, the heptane was decanted and the silica gel was extracted twicewith 200 ml portions of boiling THF. The THF solutions afforded aquantitative yield of thio-bis (polyisobutyl lactone acid) as indicatedby infrared analysis. The product analyzed for 1.51% S.

EXAMPLE B8 Bridging of Silica Gel-Bound Cl-PIBSA with SCl₂

About 100 g of Diels-Alder PIBSA having a M_(n) of 751 and asaponification number of 80 were dissolved in 500 ml of pentane andmixed with 300 g of silica gel. The mixture was stirred at roomtemperature for about 12 hours and the pentane phase was decanted. Thesilica gel was washed twice with 500 ml of pentane and the pentanefraction was evaporated. About 54 g of PIBSA were left on the silicagel. Then, 500 ml of heptane were added and the mixture was well stirredwhile 3.3 g (ca 0.027 mole, 85% purity) of sulfur dichloride were addeddropwise. The mixture was stirred at room temperature for one hour. Agel chromatogram of sulfur-bridged PIBSA sample desorbed from silica gelwith THF featured a maximum peak at M_(n) 606. The GPC of the startingPIBSA exhibited a maximum peak at 465. The reaction mixture containing 2grams of water, was then refluxed in heptane for 12 hours. Thereafter,the heptane was decanted and the silica gel was extracted with 500 ml ofTHF twice, giving 22 g of partially lactonized bridged product whichfeatured a GPC with a maximum peak at M_(n) 550. The silica gel was thenextracted twice more with 500 ml of hot THF to yield 15 g of a lactoneacid product which featured a gel chromatogram with maximum peak atM_(n) 580.

C. ESTERIFICATION OF MODEL THIO-BIS-ACYLATING AGENTS

In the following examples, the conventional ester synthesis and templateprocedures are employed in the design of polyol and polyalkylene glycolesters of model thio-bis-(acylating reagents) comprizingthio-bis-(lactone acids) and adducts of S_(x) Cl₂ and olefin diacidderivatives. In the equimolar reaction, the conventional route usuallyaffords mixtures of cyclic and linear ester products, while the templateprocedure provides mixtures of ester product enriched with 1:1, 2:2 andlarger macrocyclic esters.

EXAMPLE C1 Bis-Pentaerythritol Ester of6,6'-Thio-Bis-(5-Neo-Pentyl-3,5-Carbolactone-1-Hexanoic Acid)

A tenth-mole (13.6 g) of pentaerythritol and 0.05 mole of thio-bridgedlactone acid (prepared via the addition of SCl₂ to diisobutenylsuccinicacid) were mixed in 100 ml of xylene, and heated to reflux. Afterheating at 180° C. for three hours, the xylene was removed byrotoevaporation, and the reaction mixture dissolved in hot acetone andfiltered (2 grams of pentaerythritol collected.) Rotoevaporation of thefiltrate gave a concentrate which featured an IR spectrum with hydroxyl,lactone carbonyl and ester carbonyl absorption bands at 2.9, 5.65 and5.73 microns.

EXAMPLE C2 Tripentaerythritol Ester of6,6'-Thio-Bis-(5-Neo-Pentyl-3,5-Carbolactone-1-Hexanoic Acid)

An equimolar mixture of tripentaerythritol 0.05 mole, 18.4 g) andthio-bridged lactone acid (prepared via sulfenylation ofdiisobutenylsuccinic acid with SCl₂) were added to 100 ml ofdimethylsulfoxide and heated to 180° C. The resulting solution wasstirred at 180°-190° C. for an hour. The IR spectrum of the reactionproduct was consistent with the expected sulfur-bridged lactone polyolester.

The preceding Examples show the preparation of said esters with areactant ratio of 1-2 moles of polyol per mole of thio-bridged lactoneacid.

EXAMPLE C3 Neo-Pentyl Glycol Ester of6,6'-Dithio-Bis-(3,5-Carbolactone-1-Undecanoic Acid) Via Alcoholysis ofthe Adduct of S₂ Cl₂ and NOSA

Two-tenths mole (42.0 g) of n-octenylsuccinic anhydride in 100 ml oftoluene was treated dropwise with 0.1 mole (13.5 g) of S₂ Cl₂ at about25° C. After stirring the reaction mixture for several hours, 0.1 mole(10.4 g) of neopentyl glycol were added portionwise over a 15-minuteperiod with external cooling, and then refluxed for 24 hours.Rotoevaporation at 100° C. for 5 hours gave the product as a residuewhich featured an IR spectrum dominated by intense ester and lactonecarbonyl absorption bands at 5.85 and 5.67 microns.

An ester product could also be realized by S₂ Cl₂ -bridging thehemiester from neopentyl glycol and n-octenylsuccinic anhydride.

EXAMPLE C4 Ethylene Glycol Ester of6,6'-Dithio-Bis-(3,5-Carbolactone-1-Undecanoic Acid) Via Alcoholysis ofthe S₂ Cl₂ -NOSA Adduct

The bridging of n-octenyl succinic anhydride (0.2 mole, 42 g) with S₂Cl₂ (0.1 mole, 13.6 g) was effected by dropwise addition of the sulfurhalide to said anhydride in 100 ml xylene at 0° C. Esterification of theresulting bridged anhydride with 0.1 mole (6.2 g) of ethylene glycolafforded a sulfur-bridged lactone ester after refluxing the reactantsfor several hours.

A lactone ester could also be designed via S₂ Cl₂ -bridging of thehemiester from n-octenylsuccinic anhydride and ethylene glycol afterrefluxing the mixture in methylene chloride for several hours.

Gel permeation chromatography of the latter ester showed the presence ofa substantial peak M_(n) of 474 consistent with an intramolecular esterof the sulfur-bridged structure.

EXAMPLE C5 2,2-Dithio-Bis-Ethanol Ester of6,11-Dipentyl-3,5:14,12-Lactone-7,10-Dithiahexadecane-1,16-Dioic Acid

Bridging of n-octenylsuccinic anhydride (0.1 mole, 21 g) with1,2-ethane-bis-sulfenyl chloride (0.05 mole) was effected in 100 ml ofchloroform at ca 25° C. via the dropwise addition of the sulfenylchloride to the anhydride. After stirring the reaction mixture overnightat ca 25° C., the thio-bridged anhydride was esterified with 0.05 mole(7.7 g) of 2,2'-dithio-bis-ethanol at reflux temperature. The presenceof the product lactone ester was confirmed by IR analysis.

EXAMPLE C6 Ester Product from Polyethylene Glycol and the Adduct of S₂Cl₂ and n-Octenyl Succinic Anhydride

(a) Without metal assistance (conventional synthesis)

One-tenth mole (55.5 g) of the adduct obtained from the reaction of 0.2mole of n-octenyl succinic anhydride and 0.1 mole S₂ Cl₂ was dissolvedin 100 ml of xylene and ca 0.1 mole (40 g) of polyethylene glycol--400were added. The reaction mixture was heated to the refluxing temperatureof the xylene. After 3 hours at about 140° C., an infrared spectrum ofthe crude mixture showed mainly lactone ester with some unreactedcarboxylic acid. The mixture was allowed to reflux overnight to assurecomplete esterification. The reaction product was washed three timeswith 100 ml of saturated aqueous Na₂ CO₃ solution and the xylene layerwas dried over MgSO₄. Rotoevaporation of the reaction mixture at 100° C.for several hours afforded a residue which featured an infrared spectrumwith characteristic absorption bands for ester and lactonefunctionality.

The GPC scan of the above product showed a peak maximum corresponding toa M_(n) of 3385.

(b) With metal assistance (template procedure)

One-tenth mole (55.5 g) of said adduct of S₂ Cl₂ and n-octenyl succinicanhydride was dissolved in 200 ml of (tetrahydrofuran) THF and mixedwith 19.9 g (0.1 mole) of copper acetate monohydrate. The reactionmixture was heated to reflux and a clear blue solution was obtained.Thereafter ca 0.1 moles (40 g) of polyethylene glycol--400 was added andthe mixture was heated to 80° C. for about 4 hours. During reflux, asolid formed and the blue color of the solution turned dark green. TheTHF was boiled off and 200 ml of toluene was added and the reactionmixture was again refluxed for two more hours to ensure completeesterification. Filtration produced 8.6 g of a greenish-yellow solidwhich turned light blue with exposure to air. Analysis showed this solidto be copper chloride. The filtrate was rinsed three times with 100 mlof saturated aqueous Na₂ CO₃ solution, then dried over MgSO₄ andconcentrated by rotoevaporation at 100° C. for 4 hours. The infraredanalysis of the residue showed absorption bands characteristic of alactone ester product. GPC analysis indicated a M_(n) of 1482 for thelactone ester.

In the following Examples thio-bis-(lactone ester) formation waseffected via option (2) wherein (i) the potassium carboxylate salt ofthio-bis-(lactone acid) was reacted with a dichloride derivative oftetraethylene glycol, (ii) the metal glycolate salt of tetraethyleneglycol was interacted with the diacid chloride of thio-bis-(lactoneacid) and finally, (iii) the metal carboxylate salt of the hemi-esterfrom tetraethylene glycol and 2 moles of NOSA was bridged with sulfurdichloride.

EXAMPLE C7 Thio-Bis-(Lactone Ester) Formation Via the Potassium Salt ofThio-Bis-(Lactone Acid)

About 24.3 g (ca. 0.05 mole) of6,6'-thio-bis-(3,5-carbolactone-1-undecanoic acid) were dissolved in 100ml of dimethylformamide (DMF) and heated to reflux in the presence of5.6 g (ca. 0.1 mole) of KOH, until all the KOH dissolved. A clearreddish-brown solution of the dipotassium salt was obtained. Then, 11.6g (ca 0.05 mole) of 1,11-dichloro-3,6,9-trioxaundecane were added. Thereaction mixture was heated to reflux for about 4 hours. At the end ofthe fourth hour, the potassium chloride that formed was filtered, andthe DMF solvent was distilled off at 100° C. under high vacuum. Theinfrared spectrum of the clear reddish, oily residue featured absorptionbands ascribable to the desired lactone ester product. Similar resultswere obtained when an excess of the dichloride reactant was used.

EXAMPLE C8 Thio-Bis-(Lactone Ester) Formation Via the Sodium Salt ofTetraethylene Glycol

About 0.1 mole of the diacid chloride of6,6'-thio-bis-(3,5-carbolactone-1-undecanoic acid) (prepared via thereaction of thionyl chloride with the lactone acid) was added to aslurry of 0.1 mole sodium glycolate of tetraethylene glycol in 100 ml ofxylene (prepared via the reaction of sodium metal and tetraethyleneglycol in refluxing xylene) under a nitrogen blanket for a period of onehalf hour. The reaction mixture was then heated to reflux in xylene fortwo hours. The sodium chloride by-product was filtered off and thexylene was evaporated with nitrogen sparging. The GPC analysis showedthat the residue had a M_(n) of 904.

The oily residue featured an infrared spectrum with characteristicabsorption bands for ester and lactone functionality.

EXAMPLE C9 Chlorosulfenylation of the Tetraethylene Glycol Hemiester ofn-Octenyl Succinic Anhydride

(a) Without metal assistance

The hemiester 0.05 mole (30.7 g) of n-octenyl succinic anhydride andtetraethylene glycol dissolved in 200 ml of THF was chlorosulfenylatedvia the dropwise addition of 0.05 moles (5.15 g) of SCl₂ to the reactionmixture.

An exothermic reaction (with HCl evolution) was observed during theaddition. The mixture was stirred overnight at room temperature and thenrefluxed in THF for 8 hours. An infrared spectrum of the solvent freeproduct showed the presence of lactone ester product. Washing achloroform solution of the product several times with 100 ml aliquots ofsaturated aqueous Na₂ CO₃ and drying over MgSO₄ afforded afterrotoevaporation, a lactone ester product analyzing for 4.22 wt. % S. Agel chromatogram of the lactone ester product featured a peak maximum ofM_(n) ≈2097.

(b) With metal assistance and SCl₂

One-tenth mole (60.4 g) of the hemiester of tetraethylene glycol andn-octenylsuccinic acid was dissolved in 200 ml of THF and heated with0.01 mole (19.9 g) of copper diacetate and a clear blue solution wasobtained. Thereafter the THF solution was allowed to cool down to roomtemperature and 0.05 mole (5.15 g) of SCl₂ were added dropwise. Anexothermic reaction took place and some solid precipitated out after afew minutes. After refluxing 8 hours, the reaction mixture was cooledand filtered (about 9 g of CuCl₂ were obtained). The solvent wasevaporated and the residue was dissolved in 200 ml chloroform washedseveral times with aqueous Na₂ CO₃, and dried. Infrared analysis showedthat the residue featured lactone and ester functionality. The productanalyzed for 5.03 wt. % S and exhibited a M_(n) of 1227 based on the GPCpeak maximum.

(c) With metal assistance and S₂ Cl₂

The same procedure as above was repeated using S₂ Cl₂. A lactone esterproduct was obtained which contained 10.54 wt. % S and featured a M_(n)of 600 based on the GPC peak maximum.

EXAMPLE C10 Bis-Pentaerythritol Ester of6,6'-Dithio-Bis-(3,5-Carbolactone-1-Heneicosanoic Acid)

The adduct of S₂ Cl₂ and octadecenylsuccinic anhydride (0.05 mole, 40.2g) was esterified with 0.1 mole (13.6 g) of pentaerythritol in refluxingxylene (100 ml). HCl evolution was observed. Partial distillation of thexylene solvent raised the reaction temperature to 180° C. Aftermaintaining reaction at 180° C. for several hours, the xylene wasremoved via rotoevaporation. Dissolution of the residue in hot acetoneclouded with ether afforded upon cooling, a solid product which featuredan IR spectrum with strong hydroxyl, lactone carbonyl, and estercarbonyl absorption bands at 3.05, 5.65 and 5.75 microns, respectively.

In the following Examples, the thio-bis-(lactone acid) derived from OSAwas esterified via the (a) conventional method and (b) the templatemethod wherein the metal template reagent e.g. tetrabutyl titanate, isadded in catalytic amounts to a mixture of polyol andthio-bis-(acylating agent).

EXAMPLE C11 Bis(2,2,6,6-Tetramethylol-1-Cyclohexanol) Ester of6,6'-Thio-Bis-(3,5-Carbolactone-1-Heneicosanoic Acid)

About 38.3 g (ca 0.05 mole) of6,6'-thio-bis-(3,5-carbolactone-1-heneicosanoic acid) were dissolved in100 ml of xylene and mixed with 22 g of TMC (0.1 mole) and 0.1 g ofp-toluenesulfonic acid. The reaction mixture was refluxed for about 11/2hour until about 8 cc of water were collected. The mixture was heatedanother hour to assure complete reaction. The xylene was removed byrotoevaporation, and the residue was dissolved in pentane and filtered.Evaporation of the pentane afforded a quantitative yield of a whitesolid which featured an infrared spectrum consistent with the titlelactone ester. The hydroxyl number for the lactone ester product wasfound to be 99.2. GPC analysis shows a M_(n) of 1783.

EXAMPLE C12 2,2,6,6-Tetramethylol-1-Cyclohexanol Ester of6,6'-Thio-Bis-(3,5-Carbolactone-1-Heneicosanoic Acid)

About 38.3 g (ca 0.05 mole) of6,6'-thio-bis-(3,5-carbolactone-1-heneicosanoic acid) dissolved in 100ml of xylene were mixed with 11 g (0.05 mole) of2,2,6,6-tetramethylol-1-cyclohexanol (TMC) and 0.1 g of p-toluenesulfonic acid. The mixture was heated to about 140°-145° C. to azeotropethe water of reaction. At the end of the third hour, the reaction wascompleted as indicated by the cessation of water and infrared analysis.The xylene was stripped off with nitrogen and the residue was dilutedwith about 1 liter of a 50/50 ether-acetone mixture. A white solidprecipitated upon cooling; filtration gave 22 g of the desired lactoneester product. Further cooling gave an additional 17 g of solid, whichwas identical to the first crop as determined by infrared analysis. Theproduct featured a hydroxyl number of 44.9 and a gel chromatogram withM_(n) ≈3555.

EXAMPLE C13 Tetrabutyl Titanate Catalyzed Esterification of6,6'-Thio-Bis-(3,5-Carbolactone-1-Heneicosanoic Acid) with2,2,6,6-Tetramethylol-1-Cyclohexanol (TMC)

About 38.3 g (ca 0.05 mole) of thio-bis-(lactone acid) derived from OSAwere dissolved in 100 ml of xylene and mixed with 11 g (ca 0.05 mole) ofTMC and 0.5 g of tetrabutyl titanate. The reaction mixture was refluxedto remove the water of reaction completely. After the third hour, thehazy solution was filtered, and the clear filtrate was rotoevaporatedunder high vacuum at 100° C. for about six hours. A waxy solid materialwas obtained which featured an IR spectrum characteristic of the desiredlactone ester. The product analyzed for 3.93 wt. % sulfur, and featureda GPC with M_(n) of 1353, a value which is consistent with the presenceof substantial amounts of macrocyclic and macrocyclic-like products.

D. ESTERIFICATION OF MACRO THIO-BIS-(ACYLATING AGENTS) WITH POLYOLS

The following Examples illustrate the esterification of Ene andDiels-Alder type thoi-bis-(polyisobutyl lactone acid),thio-bis-(polybutene diacid anhydride) and adducts of S_(x) Cl₂ andPIBSA with 1-2 moles of polyols such as pentaerythritol andtripentaerythritol.

EXAMPLE D1 Bis-Pentaerythritol Ester of Thio-Bis-(Polyisobutyl LactoneAcid)

Approxmimately 0.01 mole (26.3 g) of the thio-bis-(polyisobutyl lactoneacid) prepared as described in Example B1 and 0.02 mole (2.8 g) ofpentaerythritol were mixed and heated to 200° C. for 2 hours. Theproduct was diluted with an equal weight of Solvent 150 Neutral oil andfiltered. Infrared analysis of the filtrate featured characteristicabsorption bands at 2.9-3.0 (hydroxyl) and a broad band in the 5.65-5.8micron region (lactone ester). The hydroxyl number for the productsolution (50 wt. %) was found to be 83 and showed a GPC peak maximum atM_(n) ≈7000.

EXAMPLE D2 Pentaerythritol Ester of Thio-Bis-(Polyisobutyl Lactone Acid)

Approximately 0.01 mole (26.3 g) of thio-bis-(polybutyl lactone acid)prepared as described in Example B2 and dissolved in 26.3 g of Solvent150 Neutral oil and 0.01 mole (1.36 g) of pentaerythritol were mixed andheated to about 130° C. The temperature was raised to 200° C. andmaintained there for 2 hours. Infrared analysis of the filtered solutionhaving about 50 wt. % a.i. showed the presence of hydroxyl, lactone andester functionality and analyzed for 0.39% sulfur. The hydroxyl numberfor the product solution was found to be 48.5.

EXAMPLE D3 Bis-Pentaerythritol Ester of Dithio-Bis-(Polyisobutyl LactoneAcid)

80 g (ca 0.03 moles) of a dithio-bis-(polyisobutyl lactone acid) productprepared as described in Example B3 was heated to 190° C. While stirringunder nitrogen blanket, 9.8 g (0.072 moles) of pentaerythritol wereadded and the stirred reaction mixture was heated to 220° C. for threehours with nitrogen sparging. At the end of the third hour, an equalamount of Solvent 150 Neutral oil was added to the residue to provide a50 wt. % a.i. solution. This solution was diluted with 200 ml of hexaneand filtered, and then rotoevaporated at 100° C. for 3 hours. Theresulting product solution disclosed an infrared spectrum with prominentcarbonyl absorption bands ascribable to the desired lactone polyol esterproduct which featured a hydroxyl number of 90.8 and a GPC with peakmaximum at M_(n) ≈4100 and 8100.

EXAMPLE D4 Bis-Pentaerythritol Ester of Thio-Bis-(Polyalkene DiacidAnhydride)

50 g (ca 0.02 moles) of the adduct prepared according to the firstparagraph of Example B3 was heated to 190° C. for 2 hours while stirringunder nitrogen. 6.5 g (0.048 mole) of pentaerythritol were added and thestirred reaction mixture was heated to 220° C. for 3 hours with nitrogensparging. At the end of the third hour, an equal volume of Solvent 150Neutral mineral oil was added to the residue to provide a 50 wt. %product solution. This solution was filtered through a filter cake ofCelite 503. The resulting product solution exhibited an infraredspectrum with prominent carbonyl absorption bands consistent with anester product, featured a hydroxyl number of 106.1, and analyzed for1.29 wt. % sulfur and 0.18 wt. % chlorine.

EXAMPLE D5 Pentaerythritol (PE) Ester of Thio-Bis-(Polyisobutyl LactoneAcid)

Approximately 200 g (0.1 mole) of a 50 wt. % active ingredient of PIBSAhaving a Sap. No. of 84 and a M_(n) of 776 in S150 neutral mineral oilobtained via the Ene process were dissolved in 200 ml of CH₂ Cl₂ andstirred at room temperature under a nitrogen atmosphere. The solutionwas chlorosulfenylated via the dropwise addition of 7.5 g (0.075 mole)of SCl₂ for a period of ten minutes while at room temperature. Hydrogenchloride evolution was observed during this process accompanied by anexothermic reaction. The mixture was stirred at room temperatureovernight; then 13.6 (0.1 mole) of PE and 0.5 g of concentrated sulfuricacid were added. The slurry was heated gradually to distill off thesolvent and then to 210°-215° C. for 3 hours while nitrogen sparging. Atthe end of the third hour the product was filtered and collected. Aninfrared spectrum of the solution product featured prominent carbonylabsorption band ascribable to the desired lactone polyol ester products.

EXAMPLE D6 Bis-2,2,6,6-Tetramethylol-1-Cyclohexanol Ester ofThio-Bis-(Polyisobutyl-Lactone Acid)

Approximately 0.025 mole of the adduct of PIBSA having a Sap. No. of 84and a M_(n) of 776 and SCl₂, prepared via the room temp. addition ofSCl₂ to a 50% a.i. PIBSA in Solvent 150 neutral mineral oil, was mixedat room temperature with 11.0 g (0.05 mole) of2,2,6,6-tetramethylolcyclohexanol. The reaction mixture was graduallyheated to 210°-215° C. for a period of 3 hours while stirring andnitrogen sparging. The lactone formation was monitored by infraredspectroscopy. At the end of the third hour (lactone ester carbonylabsorptions in IR reached maximum), the solution product was filteredand collected. The product showed prominent absorption bandscharacteristic of lactone and ester functionality.

EXAMPLE D7 Tripentaerythritol Ester of Dithio-Bis-(Polyisobutyl LactoneAcid)

Approximately 153 g (0.15 mole) of polyisobutenyl succinic anhydride(M_(n)) of 757 having a Sap. No. of 112 and prepared via the Enereaction of PIB and maleic anhydride were dissolved in 200 ml of THF andstirred at room temperature under a nitrogen blanket. Thereafter 10.7 g(0.077) of S₂ Cl₂ were added dropwise for a period of 15 minutes. Themixture was stirred overnight at room temperature.

Approximately 56 g of the above solution containing about 0.01 mole ofthe adduct was mixed with 3.7 g (0.01 mole) of tripentaerithritol andgradually heated to 200°-210° C. for 3 hours while nitrogen sparging.

At the end of the third hour the reaction product was mixed with anequal weight of Solvent 150 neutral mineral oil. The filtered productfeatured and infrared spectrum with absorption bands at 2.9-3.0 microns,and a broad band at 5.75-5.85 microns characteristic of hydroxyl,lactone and ester functionality.

EXAMPLE D8 Reaction Product of the Adduct of S₂ Cl₂ and PIBSA withTripentaerythritol

210 g (ca. 0.15 mole) of PIBSA, M_(n) of 1050 and a Sap. No. of 78.9),were heated to 100° C. while stirring under nitrogen. Then, 13.6 g (0.1mole) of S₂ Cl₂ were added dropwise over a period of 15 minutes. Uponcompletion of the addition, the reaction mixture was nitrogen spargedfor one-half hour at 100° C. Then 70 g (ca. 0.025 mole) of thedithio-bis-(polyisobutylsuccinic anhydride) prepared as above were mixedwith 9.3 g (0.025 mole) of tripentaerythritol and gradually heated to215° C. The reaction mixture was kept at 215° C. for 3 hours withnitrogen sparging. At the end of the third hour, an equal weight ofSolvent 150 neutral mineral oil was added and the oil solution wasfiltered. The filtrate featured an IR spectrum characteristic of thepolyol ester compounds and analyzed for 0.72 wt. % sulfur.

EXAMPLE D9 Pentaerythritol Ester of an SCl₂ PIBSA Adduct

70 g (ca 0.05 mole) of PIBSA M_(n) of 1080 and a Sap. No. of 78.9, werereacted successively with 4.0 g (0.04 mole) of SCl₂ and 8.1 g (0.06mole) of pentaerythritol, according to Example D8. The product solutionfeatured an infrared spectrum with hydroxyl absorption at 2.9 micronsand intense ester carbonyl absorption in the 5.75-5.85 micron region.The ester product analyzed for 0.54% sulfur, 0.3% Cl and showed ahydroxyl number of 46.9.

EXAMPLE D10 Bis-Pentaerythritol Ester of a S₂ Cl₂ -PIBSA Adduct

Seventy grams (ca 0.05 mole) of the PIBSA used in Ex. D9 wassulfenylated with 4.4 g (0.33 mole) of S₂ Cl₂ at 25° C. and thenesterified with 8.2 g (0.06 mole) of pentaerythritol at 210° C. for 3hours. The infrared spectrum of the final product solution showedabsorption bands similar to those in Example D9.

Pentaerythritol Ester of an SCl₂ -PIBSA Adduct Formed at 100° C.

Approximately 100 g of polyisobutenyl succinic anhydride of M_(n) 776 byGPC and having a saponification number of 84 were charged into areaction flask and heated to 100° C. Thereafter 13.6 g (0.1 mole) of S₂Cl₂ were added while stirring at 100° C. under a nitrogen atmosphere,for a period of one half hour. When the addition was completed thereaction mixture was kept at 100° C. for one half hour and then nitrogensparged for another half hour. The adduct analyzed for 1.25 wt. %chlorine.

While keeping the reaction temperature at 100° C., 16.3 g (0.12 mole) ofpentaerythritol were added and the reaction temperature was graduallyraised to 210°-215° C. for a period of 3 hours. At the end of the thirdhour an equal amount of Solvent 150 neutral mineral oil was added andthe product was filtered. An analysis of the product solution showed0.36 wt. 5 Cl and 2.05 wt. % S and a hydroxyl number of 66.1. Aninfrared spectrum of the product featured several broad absorption bandsconsistent with polyol ester product.

EXAMPLE D12 Bis-Pentaerythritol Ester of the S₂ Cl₂ -PPSA Adduct

Approximately 122 g (ca. 0.1 mole) of a polypropenylsuccinic anhydride(PPSA), (prepared by the Ene process using polypropylene and maleicanhydride), having a M_(n) of 623 by GPC (peak maximum at M_(n) 938) anda saponification number of 92, were dissolved in 200 ml of THF andstirred at room temperature under a nitrogen blanket. Then, the aboveproduct was chlorosulfenylated via the dropwise addition of 6.8 g (0.05mole) of S₂ Cl₂ at room temperature. The reaction mixture was stirred atroom temperature for 24 hours and then rotoevapgrated under high vacuum90° C. for two hours.

About 60 g (ca 0.025 mole) of the adduct prepared according to the aboveparagraph were mixed with 66 g of mineral oil S150 neutral and 8.1 g(0.06 mole) of PE and gradually heated to 215° C. The reactiontemperature was kept at 215° C. for 3 hours with nitrogen sparging.After the third hour, the product was filtered and collected. Theresulting product solution featured an infrared spectrum with prominentester carbonyl absorption bands consistent with the desired product.

EXAMPLE D13 Pentaerythritol Ester of a Dehydrochlorinated SCl₂ -Cl-PIBSAAdduct (Diels-Alder)

Aproximately 150 g of PIBSA of M_(n) 1044, having a saponificationnumber of 103, were heated to 100° C. While stirring under a nitrogenatmosphere, 15.5 g of SCl₂ were added dropwise for a period of 10minutes, and then sparged with nitrogen for half hour. At this point, 80g of Solvent 150 neutral mineral oil were added and the reactiontemperature was raised to 200° C.; thereafter 20.6 g of PE were addedand the mixture was heated at 215° C. for 3 hours under a nitrogenblanket. At the end of the third hour, 90 g of S150 neutral were addedand the product was sparged with nitrogen for another hour. The filteredproduct analyzed for 0.46% sulfur.

EXAMPLE D14 Pentaerythritol Ester of an SCl₂ -Cl-PIBSA Adduct(Diels-Alder)

Approximately 2000 g of a PIBSA of M_(n) of 1044, having asaponification number of 103 were dissolved in 4 liters of heptane andfiltered through a filter cake of celite. The heptane was distilled offuntil constant weight and the residue analyzed for a saponificationnumber of 90.2.

About 1500 g (ca 1.21 mole) based on a Sap. No. of 90.2 were heated to100° C., and 103 g (1 mole) of SCl₂ were added dropwise over a period ofone half hour. The stirred solution was kept at 100° C. for one halfhour and then sparged with nitrogen for another half hour. At this point450 g of solvent 150 neutral mineral oil and 190 g (1.39 mole) of PEwere added and the reaction mixture was gradually heated to 215° C. for3 hours with nitrogen sparging. At the end of the third hour, 1227 g ofsolvent 150 neutral were added and the product solution was sparged withnitrogen for another hour.

The filtered reaction mixture was analyzed for 0.45 wt. % S, andfeatured a hydroxyl number of 37.0

EXAMPLE D15 Pentaerythritol Ester of an S₂ Cl₂ -Cl-PIBSA Adduct(Dield-Alder)

One hundred fifty grams (ca. 0.14 mole) of polyisobutenylsuccinicanhydride (M_(n) of 1055 and Sap. No. of ca 103) were successivelyreacted with 13.5 g (0.1 mole) of sulfur monochloride and 22.5 g (0.16mole) of pentaerythritol as described in Example D13. The infraredspectrum of the residue featured broad bands at (2.9-3.0) microns and5.75-5.85 microns. After dissolution in an equal weight of S150N mineraloil, the ester product analyzed for 0.61 wt. % sulfur.

EXAMPLE D16 Pentaerythritol Ester of an SCl₂ -Cl-PIBSA Adduct(Diels-Alder)

The procedure of Example D13 was followed except that the PIBSA (150 g)had a M_(n) of 771 and a Sap. No. of 112, the amount of S₂ Cl₂ was 20.3g and the amount of pentaerythritol was 20.6 g (0.15 mole). The reactionproduct was dissolved in an equal weight of Solvent 150N mineral oil andanalyzed for 0.61 wt. % sulfur.

EXAMPLE D17 Pentaerythritol Ester of an S₂ Cl₂ -Cl-PIBSA Adduct(Diels-Alder)

The procedure of Example D13 was followed except that 20.3 g of S₂ Cl₂and 20.6 g (0.15 mole) of pentaerythritol were used and one-half, i.e.about 80 g of S150N mineral oil, was added prior to the addition ofpentaerythritol and the balance, i.e. 80 g, of S150N mineral oil wasadded after esterification. The filtered reaction product analyzed for0.78 wt. % sulfur.

EXAMPLE D18 Bis-Pentaerythritol Ester of a Dehydrochlorinated S₂ Cl₂-PIBSA Adduct

26.5 g of the dithio-bis-(polyisobutenylsuccinic anhydride) productprepared in Example B5 was mixed with 2.9 g (ca 0.022 moles) ofpentaerythritol and heated to 200°-220° C. for 3 hours with stirring andnitrogen sparging. At the end of the third hour, an equal weight ofSolvent 150 neutral oil was added to the residue to provide a 50 wt. %a.i. solution. The reaction mixture was filtered through a cake ofCelite. The resulting product solution disclosed an infrared spectrumwith broad hydroxyl and carbonyl absorption bands consistent with thebis-(pentaerythritol ester) of dithio-bis-(polybutylsuccinic acid).

EXAMPLE D19 Bis-Pentaerythritol Ester of Dehydrochlorinated S₂ Cl₂-Cl-PIBSA Adduct (Diels-Alder)

About 312 g (ca 0.28 mole) of PIBSA having a M_(n) of 1044 and asaponification number of 103 was charged into a reaction flask anddissolved in 300 ml of methylene chloride while stirring under anitrogen at 25° C. Thereafter 18.9 g (ca 0.14 mole) of S₂ Cl₂ were addeddropwise for a period of one half hour. The stirred reaction mixture wasallowed to stand at room temperature for about 20 hours.

Approximately one third (ca. 0.037 mole) of the above mixture was heatedto distill off the solvent and then kept at 160° C. for one hour.Hydrogen chloride evolution was observed during this period. A sample ofthis mixture analyzed for 0.50 wt. % Cl and 2.31 wt. % S. At this point,12.4 g (0.091 mole) of pentaerythritol were added and the mixture wasgradually heated to 210°-215° C. for three hours while nitrogensparging. The resulting product was dissolved in hexane, filtered, androtoevaporated at 100° C. under high vacuum until constant weight. Theresidue was dissolved in an equal weight of solvent 150 neutral mineraloil. The infrared spectrum of said product solution was consistent witha polyol ester product. EXAMPLE D20

Borated Pentaerythritol Ester of Dithio-Bis-(Polyisobutyl Lactone Acid)

50 g of the product solution of Example D3 and 1.1 g of boric acid wereheated at 120° C. for 2 hours and then filtered hot. The resultingborated product solution contained 0.38 wt. % boron and 1.69 wt. %sulfur. The product solution of Example D3 prior to the above borationstep featured an infrared spectrum with a prominent hydroxyl absorptionband at 2.9 microns. This band was substantially reduced in the infraredspectrum of the borated product solution of Example 20.

Boron compounds useful in the boration reaction of the oil-solublepolyol esters of thio-bis-(hydrocarbyl substituted acid materials) ofthe invention include boron oxide, boron oxide hydrate, boron acids suchas boronic acid (e.g., alkyl-B(OH)₂ or aryl-B(OH)₂) and boric acids,preferably H₃ BO₃, and esters of such boron acids.

Specific examples of boronic acids include methyl boronic acid,phenylboronic acid, cyclohexyl boronic acid, p-heptylphenyl boronic acidand dodecyl boronic acid.

The boric acid esters include mono-, di- and tri-substituted organicesters of boric acid with alcohols or phenols such as e.g., butanol,octanol, cyclohexanol, cyclopentanol, ethylene glycol, 1,3-butanediol,2,4-hexaneidol, polyisobutene substituted phenols. Lower alcohols,1,2-glycols, and 1,3-glycols, i.e., those having less than about 8carbon atoms are especially useful for preparing the boric acid estersfor the purpose of this invention. Methods for preparing the esters ofboron acid are known and disclosed in the art (such as "ChemicalReviews" pages 959-1064, volume 56).

The general process of forming the oil-soluble borated, polyol esters ofthio-bis-(hydrocarbyl substituted acid materials) of the invention byreacting the thio-bis-(lactone polyol ester) with the boron containingcompound is usually carried out by heating a mixture of the reactants ata temperature above about 60° C., preferably within the range of about80° C. to about 200° C. However, when boric acid or oxide is employed,the process is carried out at a temperature (such as 100° C. to 180° C.)preferably at about 140° C. The use of a solvent such as benzene,toluene, naphtha, mineral oil, xylene, n-hexane, or the like is oftendesirable in the above process to facilitate the control of the reactiontemperature and removal of water; mineral oil is preferred to facilitatethe products use as a lubricating oil additive.

The oil-soluble thio-bis-(lactone polyol ester) reacts readily with theboron compound, e.g., boric acid at these mildly elevated temperaturesto form the boron esters of the invention. If water of reaction isformed in the reaction as with the preferred boric acid, it is necessaryto remove all or a part of it from the reaction mixture by separating itoverhead either by blowing with an inert gas such as nitrogen or bysimple azeotropic distillation.

Boration of the materials should provide from about 0.1 to 2.0 wt. %,preferably 0.2 to 1.0 wt. %, boron based on the weight of said material.

EXAMPLE D21 Pentaerythritol Ester of PIBSA

About 0.1 mole (200 g of a 51 wt. % solution in S150N oil) of PIBSAhaving a Sap. No. of 84 and M_(n) of 776 and 13.6 g (0.1 mole) ofpentaerythritol were mixed and heated to 200° C. The reaction mixturewas stirred at 200° C. for about 3 hours and then filtered. The filtrate(50% a.i.) featured an infrared spectrum with a strong ester carbonylabsorption band at 5.8 microns and analyzed for 5.04% oxygen. Thehydroxyl number for the ester product in solution (50 wt. % a.i.) wasdetermined to be 57.4. GPC analysis revealed that the peak maximum forthis type of commercial dispersant was about 25,000.

EXAMPLE D22 Sludge Inhibition Bench (SIB) Test

The products of the above examples were subjected to a Sludge InhibitionBench (SIB) Test which has been found after a large number ofevaluations, to be an excellent test for assessing the dispersing powerof lubricating oil dispersant additives.

The medium chosen for the Sludge Inhibition Bench Test was a usedcrankcase mineral lubricating oil composition having an originalviscosity of about 325 SUS at 100° F. that had been used in a taxicabthat was driven generally for short trips only, thereby causing abuildup of a high concentration of sludge precursors. The oil that wasused contained only a refined base mineral lubricating oil, a viscosityindex improver, a pour point depressant and zinc dialkyldithiophosphateantiwear additive. The oil contained no sludge dispersants. A quantityof such used oil was acquired by draining and refilling the taxicabcrankcase at 1,000-2,000 mile intervals.

The Sludge Inhibition Bench Test is conducted in the following manner.The aforesaid used crankcase oil, which is milky brown in color, isfreed of sludge by centrifuging for 1/2 hour at about 39,000 gravities(gs.). The resulting clear bright red supernatant oil is then decantedfrom the insoluble sludge particles thereby separated out. However, thesupernatant oil still contains oil-soluble sludge precursors which onheating under the conditions employed by this test will tend to formadditional oil-insoluble deposits of sludge. The sludge inhibitingproperties of the additives being tested are determined by adding toportions of the supernatant used oil, a small amount, such as 0.5 wt. %,on an active ingredient basis, of the particular additive being tested.Ten grams of each blend being tested is placed in a stainless steelcentrifuge tube and is heated at 280° F. for 16 hours in the presence ofair. Following the heating, the tube containing the oil being tested iscooled and then centrifuged for 30 minutes at about 39,000 gs. Anydeposits of new sludge that form in this step are separated from the oilby decanting the supernatant oil and then carefully washing the sludgedeposits with 15 ml of pentane to remove all remaining oil from thesludge. Then the weight of the new solid sludge that has been formed inthe test, in milligrams, is determined by drying the residue andweighing it. The results are reported as milligrams of sludge per 10grams of oil, thus measuring differences as small as 1 part per 10,000.The less new sludge formed the more effective is the additive as asludge dispersant. In other words, if the additive is effective, it willhold at least a portion of the new sludge that forms on heating andoxidation, stably suspended in the oil so it does not precipitate downduring the centrifuging.

Using the above-described test, the dispersant activity of the additivecompounds according to the present invention were compared with thepentaerythritol ester of PIBSA (product of Example D21) and acommercially available dispersant (Lz 936) sold by the LubrizolCorporation of and is believed to be a 60 wt. % mineral oil solution ofa ca. equimolar reaction product of PIBSA and pentaerythritol with M_(n)25,000 by GPC. The test results are given in Table I.

                  TABLE I                                                         ______________________________________                                        SLUDGE DISPERSANCY TEST RESULTS                                               Test       Additive  Mg Sludge/10 g Oil at                                    Sample     of Example                                                                              0.5 wt. %                                                ______________________________________                                        I-1        D3        1.2                                                      2          D21       7.4                                                      3          D19       3.2                                                      4          D15       2.04                                                     5          D16       3.6                                                      6          D17       2.1                                                      7          D18       3.2                                                      8          D4        2.4                                                      9          Lz 936    10.2, 6.4                                                10         Blank     10.0                                                     ______________________________________                                    

The results set forth in Table I show that the sulfur-bridged polyolester dispersants according to the present invention are more effectivesludge dispersants than the commercial type pentaerythritol esters ofPIBSA, i.e. Example D21 and Lz 936 (sold commercially by LubrizolCorporation as a sludge dispersant for lubricating oils).

EXAMPLE D23 Evaluation of Products in Varnish Inhibition Bench (VIB)Test

Each test sample consisted of 10 grams of lubricating oil containing0.07 of a gram of the additive concentrate (50% active) which results ina total of 0.35 wt. % additive present in the test sample. The test oilto which the additive is admixed was 9.93 grams of a commerciallubricating oil obtained from a taxi after 2,000 miles of driving withsaid lubricating oil. Each ten gram sample was heat soaked overnight atabout 140° C. and thereafter centrifuged to remove the sdudge. Thesupernatant fluid of each sample was subjected to heat cycling fromabout 150° C. to room temperature over a period of 3.5 hours at afrequency of about 2 cycles per minute. During the heating phase, thegas containing a mixture of about 0.7 volumes percent SO₂, 1.4 volumepercent NO and balance air was bubbled through the test samples andduring the cooling phase water vapor was bubbled through the testsamples. At the end of the test period, which testing cycle can berepeated as necessary to determine the inhibiting effect of anyadditive, the wall surfaces of the test flasks in which the samples werecontained are visually evaluated. Flasks in which the samples werecontained are visually evaluated as to the varnish inhibition. Theamount of varnish imposed on the walls is rated at values of from 1 to 7with the higher number being the greater amount of varnish. It has beenfound that this test correlates with the varnish results obtained as aconsequence of carrying out an MS-VC engine test. The results of the VIBtesting of candidate and commercial dispersants are recorded in table IIbelow:

                  TABLE II                                                        ______________________________________                                        0.5 WEIGHT PERCENT OF ADDITIVE                                                ADDED TO TEST OIL                                                             Test          Additive of                                                                             VIB                                                   Sample        Example   Rating                                                ______________________________________                                        II-1          D3        4                                                     2             D21       5-6                                                   3             D19       2                                                     4             D15       3                                                     5             D18       3                                                     6             D17       3                                                     7             D4        4                                                     8             D20       4                                                     9             Lz 936    4                                                     10            Blank     11                                                    ______________________________________                                    

The data in Table II illustrate the outstanding varnish-inhibitionactivity of the additive compounds (including a borated derivative--seeTest Sample II-8) according to the present invention when compared withcommercial-type pentaerythritol esters of PIBSA, i.e. Test Samples II-2and -9, the latter being sold commercially as a sludge dispersant forlubricating oils by the Lubrizol Corporation.

EXAMPLE D24

The utility of the inventive additives was also measured by subjectingthe product of Example D8 to a standard engine test of a blendedformulation containing this additive. A 15W/50 SAE crankcase oilformulation was made up using 12.5 wt. % of the oil concentrate ofExample D8, 2 volume % of an ashless dispersant additive, 1.1 volume %of an overbased magnesium sulfonate, 0.8 volume % of overbased calciumphenate, 0.5 volume % of an antioxidant, and 1.43 volume % of a zincdialkyldithiophosphate and a mineral lubricating oil blend of basestocks. The above formulation was tested in the Sequence V-C EngineTest, which is described in "Multicylinder Test Sequences for EvaluatingAutomotive Engine Oils", ASTM Special Technical Publication 315F, page133ff (1973). The V-C test evaluates the ability of a formulated oil tokeep sludge in suspension and prevent the deposition of varnish depositson pistons, valves, and other engine parts. The MS-VC test results forExample are illustrated in Table III.

                  TABLE III                                                       ______________________________________                                                  MS-VC Test Results                                                                     Piston Skirt                                                                            Total                                                      Sludge   Varnish   Varnish                                          ______________________________________                                        Oil with Product                                                              of Ex. D8   9.3        8.0       7.9                                          Passing Criteria                                                              for Test    8.5        7.9       8.0                                          ______________________________________                                    

In the above tests, the ratings are on a scale of 0 to 10, with 0 beingan excessive amount of sludge and varnish while 10 being a completelyclean engine. The formulated oil containing the additive of theinvention (Example D8) passed.

EXAMPLE D25

Seven of the sulfur-bridged polyol ester products of the presentinvention and two commercial polyol ester dispersant additives dilutedin mineral oil were evaluated by thermo gravimetric analysis (TGA) forevidence of thermal stability under oxidative conditions provided by airflow across each sample heated linearly from about 50° C. to 450° C. ata rate of 6°/min. Each sample of 200 mg in a stainless steel planchettewas continuously weighed and recorded as the temperature was programmedupwardly at a linear rate to provide a record of sample weight versustemperature. The results are found in Table IV.

                  TABLE IV                                                        ______________________________________                                                         Temperature at which the indicated                           Test  Product    percentage weight loss occurred                              Sample                                                                              Additive   10 Wt. % 50 Wt. %                                                                             70 Wt. %                                                                             90 Wt. %                              No.   Tested     °C.                                                                             °C.                                                                           °C.                                                                           °C.                            ______________________________________                                        1     Solvent 150N                                                                             230      283    295    310                                         Mineral Oil                                                             2     Lz 936*    220      317    375    417                                   3     Ex. D21    245      315    365    410                                   4     Ex. D19    265      360    415    450                                   5     Ex. D4     280      387    420    450                                   6     Ex. D3     270      375    410    437                                   7     Ex. D13    265      345    400    442                                   8     Ex. D20    270      380    413    430                                   9     Ex. D7     263      350    413    452                                   10    Ex. D10    265      350    400    437                                   ______________________________________                                         *Lubrizol Lz 936 is a commercial dispersant for lubricant oils sold by        Lubrizol Corp., Ohio.                                                    

The TGA data shown in Table IV reveal that the compositions of thepresent invention are significantly more stable towards heat andoxidation than the reference commercial PIBSA polyol ester dispersants,Lz 936 and Ex. D21. In addition, the TGA data show that thethio-bis-(polyol esters) of the present invention tends to stabilize thebase oil, e.g. S-150N base stock oil, towards thermal oxidativedegradation. Thus, the novel structural features built into the preseftdispersants endow these additives with enhanced thermal stability aswell as the ability to inhibit oxidation of the base stock oil. It isbelieved that these inhibitor properties can be related in part to thepresence of sulfide functionality present in the additive molecules ofthe present invention.

What is claimed is:
 1. Reaction product of an adduct of S₂ Cl₂ andpolyisobutenylsuccinic anhydride with tripentaerythritol obtained byfirst coreacting at temperatures of from -60° C. to about 100° C. S₂ Cl₂with polyisobutenylsuccinic anhydride in a 1:2 molar ratio to formdithio-bis-(polyisobutenylsuccinic anhydride), and thereafter coreactingat temperatures of from 20° C. to 240° C. saiddithio-bis-(polyisobutenylsuccinic anhydride) with tripentaerythritolrepresented by the formula ##STR23## in a 0.5:1 to 1:1 molar ratio. 2.Pentaerythritol ester of thio-bis-(polyisobutenylsuccinic acid)represented by the formula ##STR24## wherein: each R is independentlyselected from hydrogen and polyisobutenyl radicals with the proviso thatat least one R is polyisobutenyl radical.
 3. Pentaerythritol ester ofdithio-bis-(polyisobutenylsuccinic acid) represented by the formula##STR25## wherein: each R is independently selected from hydrogen andpolyisobutenyl radicals with the proviso that at least one R ispolyisobutenyl radical.